PENGELOLAAN
RUANG TERBUKA HIJAU
KOTA
smno2ub.ac.id2014
Alvey, A.A. 2006. Promoting and preserving biodiversity in the urban forest. Urban Forestry &
Urban Greening, 5 (4): 195–201.
Efforts at mitigating global biodiversity loss have often focused on preserving large,
intact natural habitats. However, preserving biodiversity should also be an important
goal in the urban environment, especially in highly urbanized areas where little natural
habitat remains. Increasingly, research at the city/county scale as well as at the
landscape scale reveals that urban areas can contain relatively high levels of
biodiversity (Alvey, 2006). Important percentages of species found in the surrounding
natural habitat, including endangered species, have been found in the urban forest.
This contribution concisely highlights some examples of urban biodiversity research
from various areas of the world. Key issues involved in understanding the patterns and
processes that affect urban biodiversity, such as the urban–rural gradient and biotic
homogenization, are addressed. The potential for urban areas to harbor considerable
amounts of biodiversity needs to be recognized by city planners and urban foresters so
that management practices that preserve and promote that diversity can be pursued.
Management options should focus on increasing biodiversity in all aspects of the
urban forest, from street trees to urban parks and woodlots.
Escobedo,F.J. , J.E. Wagner, D.J. Nowak, C. Luz De la Maza, M. Rodriguez dan D.E. Crane, 2008.
Analyzing the cost effectiveness of Santiago, Chile's policy of using urban forests to improve air
quality. Journal of Environmental Management, 86 (1): 148–157.
Santiago, Chile has the distinction of having among the worst urban air pollution problems in
Latin America. As part of an atmospheric pollution reduction plan, the Santiago Regional
Metropolitan government defined an environmental policy goal of using urban forests to
remove particulate matter less than 10 μm (PM10) in the Gran Santiago area. Escobedo et al.
(2008) used cost effectiveness, or the process of establishing costs and selecting least cost
alternatives for obtaining a defined policy goal of PM10 removal, to analyze this policy goal. The
PM10 removal by Santiago's urban forests based on socioeconomic strata and using field and
real-time pollution and climate data via a dry deposition urban forest effects model. Municipal
urban forest management costs were estimated using management cost surveys and Chilean
Ministry of Planning and Cooperation documents. The managing municipal urban forests (trees,
shrubs, and grass whose management is under the jurisdiction of Santiago's 36 municipalities)
to remove PM10 was a cost-effective policy for abating PM10 based on criteria set by the World
Bank. The cost effectiveness of managing municipal urban forests and street trees to other
control policies (e.g. alternative fuels) to abate PM10 in Santiago and determined that municipal
urban forest management efficiency was similar to these other air quality improvement
measures.
Nielsen,A.B. dan F. Møller. 2008. Is coppice a potential for urban forestry? The social
perspective. Urban Forestry & Urban Greening, 7 (2): 129–138.
After years of decline and neglect, low woodland types based on coppice management
experience renewed interest. Substantial research has demonstrated the potentials of
coppice for biomass production and for nature conservation, and coppices are
increasingly being suggested for urban situations (Nielsen dan Møller, 2008). The
understanding of the more social aspects of coppice woodlands in modern urban
situations is limited. This contribution classifies coppice management systems as a
basis for identification of social aspects of coppices and their potential use in
contemporary urban forestry. Based on this classification, the social perspectives and
potential niches for urban coppices are discussed, while lines of research are
suggested which will support the development of a thorough and up-to-date
knowledge base, against which the social merits of urban coppice woodlands can be
critically evaluated.
Randrup,T.B. dan B.Persson. 2009. Public green spaces in the Nordic countries: Development of
a new strategic management regime. Urban Forestry & Urban Greening, 8 (1): 31–40.
Park authorities in the Nordic countries were studied for the first time in a combined
survey (Randrup dan Persson, 2009). Major similarities were found between
countries, but also interesting differences. These differences are believed to be
essential in understanding how to share experiences between the countries. The need
for strategic green space management (SGSM), which operates on three levels within
the organisation; operations, tactics, and policies. A theoretical description of SGSM is
presented for future consideration and inspiration in practice as well as in research.
. Urban Forestry & Urban Greening, 3 (2): 65–78.
The urban forest in Beijing and its role in air pollution reduction
Jun Yanga, , , Joe McBridea, Jinxing Zhoub, Zhenyuan Sun. 2005.
Tree planting has been proposed by the municipal government as a measure to
alleviate air pollution in Beijing, the capital of China. This study examines that
proposal. It is based on the analyses of satellite images and field surveys to establish
the characteristics of current urban forest in the central part of Beijing. The influence
of the urban forest on air quality was studied using the Urban Forest Effects Model.
The results show that there are 2.4 million trees in the central part of Beijing. The
diameter distribution of the trees is skewed toward small diameters. The urban forest
is dominated by a few species. The condition of trees in the central part of Beijing is
not ideal; about 29% of trees were classified as being in poor condition. The trees in
the central part of Beijing removed 1261.4 tons of pollutants from the air in 2002. The
air pollutant that was most reduced was PM10 (particulate matters with an
aerodynamic diameter smaller than 10 μm), the reduction amounted to 772 tons. The
carbon dioxide (CO2) stored in biomass form by the urban forest amounted to about
0.2 million tons. Future research directions to improve our understanding of the role
of individual tree species in air pollution reduction are discussed.
. Journal of Environmental Psychology, 11 (3): 201–230.
Stress recovery during exposure to natural and urban environments.
R.S. Ulrich., R. F. Simons, B.D. Losito, E.Fiorito, M.A. Miles, M. Zelson. 1991.
Different conceptual perspectives converge to predict that if individuals are stressed, an
encounter with most unthreatening natural environments will have a stress reducing or
restorative influence, whereas many urban environments will hamper recuperation. Hypotheses
regarding emotional, attentional and physiological aspects of stress reducing influences of
nature are derived from a psycho-evolutionary theory. To investigate these hypotheses, 120
subjects first viewed a stressful movie, and then were exposed to color/sound videotapes of one
of six different natural and urban settings. Data concerning stress recovery during the
environmental presentations were obtained from self-ratings of affective states and a battery of
physiological measures: heart period, muscle tension, skin conductance and pulse transit time, a
non-invasive measure that correlates with systolic blood pressure. Findings from the
physiological and verbal measures converged to indicate that recovery was faster and more
complete when subjects were exposed to natural rather than urban environments. The pattern
of physiological findings raised the possibility that responses to nature had a salient
parasympathetic nervous system component; however, there was no evidence of pronounced
parasympathetic involvement in responses to the urban settings. There were directional
differences in cardiac responses to the natural vs urban settings, suggesting that
attention/intake was higher during the natural exposures. However, both the stressor film and
the nature settings elicited high levels of involuntary or automatic attention, which contradicts
the notion that restorative influences of nature stem from involuntary attention or fascination.
Urban Forestry & Urban Greening, 2 (2): 115–124.
Tree protection legislation in European cities
Ariane Schmieda, Werner Pillmann. 2003.
In this study, a survey on regulations and legal requirements concerning tree protection in
European cities has been elaborated. It is designed as an information source for decision
support in legal development, city planning and nature conservation. The survey is based on
questionnaires on the one hand and on laws, ordinances and regulations on the other. Out of
the 34 cities which were contacted or for which legal documents were found on the Internet, 25
(74%) have laws protecting trees in public and/or private areas. Against the background of rising
ecological awareness, most of the laws were adopted from the 1970s onward.
In most cases the protection of a tree is regulated by means of the circumference or the
diameter of the stem, while sometimes the height of the tree is the criterion on which
protection depends. In other cases, protection is granted if a tree is growing in a protected area
or if the tree is submitted to a “Tree Preservation Order”. In all 25 cities the felling of protected
trees is subjected to an official authorisation. In many laws interdictions concerning trees are
listed. Most frequently, it is prohibited to cut down, to remove, to fell, to damage, to destroy, to
modify, and to prune protected trees, and to enhance their decay.
A law concerning tree protection seems to make sense, if it can be implemented in a nonbureaucratic, professional and efficient way, respecting the protection and conservation of
nature. It should be structured simply and equitably, and its administration and implementation
should be simple and efficient.
Urban Forestry & Urban Greening, 9 (2): 93–100.
Social interactions in urban parks: Stimulating social cohesion?
Karin Peters, , , Birgit Elands , Arjen Buijs. 2010.
People from all ethnic backgrounds spend some of their leisure time in green areas.
This study found that urban parks are more inclusive green places than non-urban
green areas, and that urban parks can promote social cohesion. The objective of the
research was to establish the extent to which urban parks facilitate social cohesion and
how social interaction and place attachment can contribute to such cohesion.
Quantitative research (a survey) and qualitative research (observations and interviews)
carried out in five urban parks in the Netherlands revealed that there are many
similarities in the ways that ethnic groups use urban parks and in the meanings of such
parks to these groups. Urban parks are sites where different ethnic groups mingle and
where informal and cursory interactions can stimulate social cohesion. Furthermore,
being involved and concerned with parks can facilitate attachment to these places.
Urban parks can provide a vital locality where everyday experiences are shared and
negotiated with a variety of people. The design of a park, its location and people's
image of the park in combination with the cultural characteristics of various ethnic
groups inform the opportunities for intercultural interactions.
. Urban Forestry & Urban Greening, 7 (2): 129–138.
Is coppice a potential for urban forestry? The social perspective
Anders Busse Nielsen, and F. Møller. 2008.
After years of decline and neglect, low woodland types based on coppice management
experience renewed interest. Substantial research has demonstrated the potentials of
coppice for biomass production and for nature conservation, and coppices are
increasingly being suggested for urban situations. Yet, our understanding of the more
social aspects of coppice woodlands in modern urban situations is limited. Against this
background, this contribution classifies coppice management systems as a basis for
identification of social aspects of coppices and their potential use in contemporary
urban forestry. Based on this classification, the social perspectives and potential niches
for urban coppices are discussed, while lines of research are suggested which will
support the development of a thorough and up-to-date knowledge base, against which
the social merits of urban coppice woodlands can be critically evaluated.
Konijnendijk, C.C. 2003. A decade of urban forestry in Europe. Forest Policy and Economics, 5
(2): 173–186.
Major changes in society have led to a call for structural changes in forestry, also in
Europe. Urbanisation as one of the major driving forces has had a clear impact on
European forestry. One of the new approaches emerging in response is the concept of
urban forestry (Konijnendijk, 2003). It was developed in North America during the
1960s as innovative approach to managing natural resources in urban environments.
Aimed at the integrated planning and management of all tree-based resources in cities
and towns, the concept found broad support in North America after initial resistance
from both foresters and urban green professionals. Similar resistance was met in
Europe, and here it took until the early 1990s before the concept of urban forestry
found broader acceptance and support. Since then, a European urban forestry
research community has emerged, as have policies, programmes and higher education
incorporating elements of urban forestry. Urban forest resources in Europe might be
small in relative terms compared to other natural resources. They do, however, cover
millions of hectares of land and provide multiple, highly demanded goods and
services. Forestry can benefit from urban forestry experiences and innovations, for
example in terms of better meeting the expectations and demands of urban society.
Urban forestry, on the other hand, is firmly rooted in some of the basic concepts of
traditional forestry, such as sustained yield.
Keeling, R.F. 1988. Measuring correlations between atmospheric oxygen and carbon dioxide
mole fractions: A preliminary study in urban air. Journal of Atmospheric Chemistry, 7(2): 153176 .
Keeling (1988) monitored the O2 and CO2 mole fraction of the air on 25 and 26
October 1986 in Cambridge, Massachusetts . The O2 concentrations were detected
from changes in the relative refractivity of dried air between two lines of 198Hg at
2537.269 and 4359.562 Å using dual-wavelength interferometry. Changes in oxygen
mole fraction were resolved with two-minute time resolution to a precision of ±2.0
ppm. Changes in O2 were shown to be strongly anticorrelated with changes in CO2 as
expected for combustion processes.
Chinese Geographical Science, 20 (2): 144-151 .
A new carbon and oxygen balance model based on ecological service of urban vegetation
Kai Yin, Qianjun Zhao, Xuanqi Li, Shenghui Cui, Lizhong Hua, Tao Lin. 2010.
The application of human induced oxygen consumption and carbon emission theory in
urban region was summed up and on this base a new model of urban carbon and
oxygen balance (UCOB) was constructed by calculating the carbon and oxygen fluxes.
The purpose was to highlight the role of vegetation in urban ecosystems and evaluate
the effects of various human activities on urban annual oxygen consumption and
carbon emission. Hopefully, the model would be helpful in theory to keep the regional
balance of carbon and oxygen, and provide guidance and support for urban vegetation
planning in the future. To test the UCOB model, the Jimei District of Xiamen City, Fujian
Province, China, a very typical urban region, was selected as a case study. The results
turn out that Jimei’s vegetation service in oxygen emission and carbon sequestration
could not meet the demand of the urban population, and more than 31.49 times of
vegetation area should be added to meet the whole oxygen consumption in Jimei
while 9.60 times of vegetation area are needed to meet the carbon sequestration
targets. The results show that the new UCOB model is of a great potential to be
applied to quantitative planning of urban vegetation and regional eco-compensation
mechanisms.
Churkina, G. 2008. Modeling the carbon cycle of urban systems. Ecological Modelling, 216 (2):
107–113.
Although more than 80% of carbon dioxide emissions originate in urban areas, the role
of human settlements in the biosphere evolution and in global carbon cycling remains
largely neglected (Churkina, 2008). Understanding the relationships between the form
and pattern of urban development and the carbon cycle is however crucial for
estimating future trajectories of greenhouse gas concentrations in the atmosphere
and can facilitate mitigation of climate change.
Churkina (2008) reviewed state-of-the-art in modeling of urban carbon cycle, started
with the properties of urban ecosystems from the ecosystem theory point of view. The
key elements of an urban system and to which degree they are represented in the
existing models. The necessity of including biophysical as well as human related
carbon fluxes in an urban carbon cycle model and necessity of collecting relevant data.
Seasonal and annual variations in the photosynthetic productivity and carbon balance of a
central Siberian pine forest. Tellus Series B , 54 (5): …
Jon Lloyd, Olga Shibistova, Daniil Zolotoukhine, Olaf Kolle, Almut Arneth, Christian Wirth, Julie
M. Styles, N. M. Tchebakova, E.-Detlef Schulze. 2002.
We present a first analysis of data (June 1998 to December 2000) from the long-term eddy covariance site
established in a Pinus sylvestris stand near Zotino in central Siberia as part of the EUROSIBERIAN
CARBONFLUX project. As well as examining seasonal patterns in net ecosystem exchange (NE), daily, seasonal
and annual estimates of the canopy photosynthesis (or gross primary productivity, GP) were obtained
using NE and ecosystem respiration measurements.
Although the forest was a small (but significant) source of CO2 throughout the snow season (typically midOctober to early May) there was a rapid commencement of photosynthetic capacity shortly following the
commencement of above-zero air temperatures in spring: in 1999 the forest went from a quiescent state to
significant photosynthetic activity in only a few days. Nevertheless, canopy photosynthetic capacity was
observed to continue to increase slowly throughout the summer months for both 1999 and 2000, reaching a
maximum capacity in early August. During September there was a marked decline in canopy photosynthesis
which was only partially attributable to less favourable environmental conditions. This suggests a reduction
in canopy photosynthetic capacity in autumn, perhaps associated with the cold hardening process. For
individual time periods the canopy photosynthetic rate was mostly dependent upon incoming photon
irradiance. However, reductions in both canopy conductance and overall photosynthetic rate in response to
high canopy-to-air vapour differences were clearly evident on hot dry days. The relationship between
canopy conductance and photosynthesis was examined using Cowan's notion of optimality in which stomata
serve to maximise the marginal evaporative cost of plant carbon gain. The associated Lagrangian multiplier
(λ) was surprisingly constant throughout the growing season. Somewhat remarkably, however, its value was
markedly different between years, being 416 mol mol−1 in 1999 but 815 mol mol−1 in 2000. Overall the forest
was a substantial sink for CO2 in both 1999 and 2000: around 13 mol C m−2 a−1. Data from this experiment,
Ecological Economics, 60 (3): 2007, Pages 533–542
An environmental accounting framework applied to green space ecosystem planning for small
towns in China as a case study
Lingxian Zhanga, Qing Liub, Nigel W. Hallc, Zetian Fu. 2007.
The paper presents a method that addresses the problem of the amount of green
space required for the environment areas of lower biodiversity by the ecological
element threshold method. The original habitat had been highly disturbed by human
activities in most developing countries. Taking the population carrying capacity, the
balance of carbon–oxygen, and the supply–demand equilibrium of water resource as a
group of conjugate restriction factors of green space planning, it quantifies the total
amount of green space required to keep the ecological system in balance for the town
of Shaliuhe, Hebei Province as the case study. The results show that the main
restrictive factor at Shaliuhe town is the imbalance between the supply and demand
for the water resource, 89.34% of which is used in agriculture. Therefore, the effects of
various ecological improvements are calculated for the years 2005, 2010 and 2015.
This case study could be used as a model for the planning of other towns on the
northeast China plain to improve the environment, ecology and sustainability.
Similarly, the Chinese scenario might provide a useable reference to other developing
countries.
Urban Ecosystems, 2014, 17 (2): 445-453 .
Pervious and impervious pavement reduce production and decrease lifespan of fine roots of
mature Sweetgum trees.
A. Volder, B.Viswanathan, W. T..Watson . 2014.
Root zones of mature Sweetgum paved with either pervious or impervious concrete after 15–
18 years of tree growth exhibited much reduced standing fine root length compared to unpaved
plots 3 years after pavement installation. The objective of this paper was to determine whether
these observed reductions in standing root length were due to reduced root production rates or
due to enhanced root mortality rates in response to the presence of either pavement. We
measured both fine root production and root death over a 15-month period using biweekly
nondestructive observations of the root zones at four depths. In addition, we used proportional
hazards analysis to determine how the presence of pavement affected chances of root mortality.
We found that new root production was more negatively affected by the presence of either
pavement than root mortality while chances of root mortality were increased by the presence of
pavement, leading to much reduced standing net root length in paved plots at any given time.
Surprisingly, even though root production and mortality were strongly altered by pavement,
there was no significant effect on tree diameter growth. These results suggest that while
Sweetgum root dynamics are negatively affected by pavement, there is enough plasticity within
this species to adapt to altered root zone dynamics without affecting aboveground growth.
Balakina, J.N., O.V. Makarova, V.V. Bondarenko, L.J. Koudstaal, E.J. Ros, A.J. Koolen, W.K.P. van
Loon. 2005. Simulation of oxygen regime of tree substrates. Urban Forestry & Urban Greening,
4 (1): 23–35.
The oxygen regime of urban tree-growing sites may be sub-optimal for tree growth
and the related ornamental value of trees. Problems may especially occur in situations
where the substrate is covered by pavement and/or where the water table is very
shallow. The stability (oxygen consumption rate) of the organic components of the
substrate (peat, green waste compost, etc.) and the design of the growing site also
play an important role. The oxygen regime of a number of designs (wide strip of
substrate; narrow strip; wide strip with multiple aeration pipes; narrow strip with one
aeration pipe) was simulated for a range of substrates with the computer program
“Matlab, pde toolbox”. Balakina, et al. (2005) computed equilibrium distributions of
oxygen in the substrates from gas diffusion coefficients of the different parts of the
growing site constructions and from the specific oxygen consumption rate of the
substrate.
The simulation results were compared with measurements on an experimental
substrate strip. In can be shown the importance of organic matter stability and
growing site design. On wide strips the presence of aeration pipes may be very
advantageous, or even necessary.
. Plant and Soil, 227 (1-2): 215-221 .
On the assessment of root and soil respiration for soils of different textures: interactions with
soil moisture contents and soil CO2 concentrations
T.J. Bouma and D.R. Bryla. 2000.
Estimates of root and soil respiration are becoming increasingly important in agricultural and
ecological research, but there is little understanding how soil texture and water content may
affect these estimates. We examined the effects of soil texture on (i) estimated rates of root and
soil respiration and (ii) soil CO2 concentrations, during cycles of soil wetting and drying in the
citrus rootstock, Volkamer lemon (Citrus volkameriana Tan. and Pasq.). Plants were grown in soil
columns filled with three different soil mixtures varying in their sand, silt and clay content. Root
and soil respiration rates, soil water content, plant water uptake and soil CO2 concentrations
were measured and dynamic relationships among these variables were developed for each soil
texture treatment. We found that although the different soil textures differed in their plant-soil
water relations characteristics, plant growth was only slightly affected. Root and soil respiration
rates were similar under most soil moisture conditions for soils varying widely in percentages of
sand, silt and clay. Only following irrigation did CO2 efflux from the soil surface vary among soils.
That is, efflux of CO2 from the soil surface was much more restricted after watering (therefore
rendering any respiration measurements inaccurate) in finer textured soils than in sandy soils
because of reduced porosity in the finer textured soils. Accordingly, CO2 reached and maintained
the highest concentrations in finer textured soils (> 40 mmol CO2 mol−1). This study revealed
that changes in soil moisture can affect interpretations of root and soil measurements based on
CO2 efflux, particularly in fine textured soils. The implications of the present findings for field soil
CO2 flux measurements are discussed.
Burton,A.J., G.P. Zogg, K.S. Pregitzer dan D.R. Zak. 1997. Effect of measurement CO2
concentration on sugar maple root respiration. Tree Physiol ., 17 (7): 421-427.
Accurate estimates of root respiration are crucial to predicting belowground C cycling in forest
ecosystems. Inhibition of respiration has been reported as a short-term response of plant tissue
to elevated measurement [CO2]. Burton et al. (1997) sought to determine if measurement [CO2]
affected root respiration in samples from mature sugar maple (Acer saccharum Marsh.) forests
and to assess possible errors associated with root respiration measurements made at [CO2]s
lower than that typical of the soil atmosphere. Root respiration was measured as both CO2
production and O2 consumption on excised fine roots (≤ 1.0 mm) at [CO2]s ranging from 350 to >
20,000 μl l−1. Root respiration was significantly affected by the [CO2] at which measurements
were made for both CO2 production and O2 consumption. Root respiration was most sensitive to
[CO2] near and below normal soil concentrations (< 1500 μl l−1). Respiration rates changed little
at [CO2]s above 3000 μl l−1 and were essentially constant above 6000 μl l−1 CO2. These findings
call into question estimates of root respiration made at or near atmospheric [CO2], suggesting
that they overestimate actual rates in the soil.
The sugar maple root respiration at atmospheric [CO2] (350 μl l−1) is about 139% of that at soil
[CO2]. Although the causal mechanism remains unknown, the increase in root respiration at low
measurement [CO2] is significant and should be accounted for when estimating or modeling root
respiration. Until the direct effect of [CO2] on root respiration is fully understood, we
recommend making measurements at a [CO2] representative of, or higher than, soil [CO2]. In all
cases, the [CO2] at which measurements are made and the [CO2] typical of the soil atmosphere
should be reported.
. Carbon and oxygen isotope ratios of ecosystem respiration along an Oregon conifer transect:
preliminary observations based on small-flask sampling . Tree Physiol (1998) 18 (8-9): 513-519.
J. R. Ehleringer and C. S. Cook. 1998.
Isotope ratio analyses of atmospheric CO2 at natural abundance have significant potential for contributing to
our understanding of photosynthetic and respiration processes in forest ecosystems. Recent advances in
isotope ratio mass spectrometry allow for rapid, on-line analysis of small volumes of CO2 in air, and open
new research opportunities at the ecophysiological, whole-organism, and atmospheric levels. Among the
immediate applications are the carbon and oxygen isotope ratio analyses of carbon dioxide in atmospheric
air. Routine analysis of carbon dioxide in air volumes of approximately 50–300 μl is accomplished by linking a
commercially available, trace gas condenser and gas chromatograph to an isotope ratio mass spectrometer
operated in continuous-flow mode. Samples collected in the field are stored in either gas-tight syringes or
100-ml flasks. The small sample volume required makes it possible to subsample the air in flasks for CO2 and
then to sample the remaining air volume for the analysis of the isotopic composition of either methane or
nitrous oxide. Reliable δ13C and δ18O values can be obtained from samples collected and stored for 1–3 days.
Longer-term storage, on the order of weeks, is possible for δ13C measurements without drift in the isotope
ratio signal, and should also be possible for δ18O measurements.
When linked with an infrared gas analyzer, pump and flask sampling system, it is feasible to sample CO2
extensively in remote forest locations. The air-sampling system was used to measure the isotope ratios of
atmospheric CO2 and to conduct a regression analysis of the relationship between these two parameters.
From the regression, we calculated the δ13C of ecosystem respiration of four coniferous ecosystems along a
precipitation gradient in central Oregon. The ecosystems along the coast-to-interior Oregon (OTTER)
gradient are dominated by spruce–hemlock forests at the wet, coastal sites (> 200 cm precipitation annually)
to juniper woodlands (20 cm precipitation) at the interior, dry end of the transect. The δ 13C values of
ecosystem respiration along this transect differed by only 1.3‰ (range of –25.2 to –23.9‰) during August at
the peak of the summer drought. Following autumn rains in September, the δ13C of ecosystem respiration in
the four stands decreased; overall the difference in the carbon isotope ratio of ecosystem respiration among
Yan-Shih Lin, B.E. Medlyn, and D.S. Ellsworth. 2012. Temperature responses of leaf net
photosynthesis: the role of component processes . Tree Physiol , 32 (2): 219-231.
The response of photosynthesis to temperature is a central facet of plant response to climate.
Such responses have been found to be highly variable among species and among studies.
Understanding this variability is key when trying to predict the effects of rising global
temperatures on plant productivity. There are three major factors affecting the response of leaf
net photosynthesis to temperature (An–T): (i) photosynthetic biochemistry, (ii) respiration and
(iii) vapour pressure deficit (D) and stomatal sensitivity to vapour pressure deficit during
measurements. The overall goal of our study was to quantify the relative contribution of each of
these factors in determining the response of An to temperature. We first conducted a sensitivity
analysis with a coupled photosynthesis–stomatal (An–gs) model, using ranges for parameters of
each factor taken from the literature, and quantified how these parameters affected the An–T
response. Second, we applied the An–gs model to two example sets of field data, which had
different optimum temperatures (Topt) of An, to analyse which factors were most important in
causing the difference. We found that each of the three factors could have an equally large
effect on Topt of An. In our comparison between two field datasets, the major cause for the
difference in Topt was not the biochemical component, but rather the differences in respiratory
components and in D conditions during measurements. We concluded that shifts in An–T
responses are not always driven by acclimation of photosynthetic biochemistry, but can result
from other factors. The D conditions during measurements and stomatal responses to D also
need to be quantified if we are to better understand and predict shifts in An–T with climate.
Clint J. Springer, E. H. DeLucia, and R.B. Thomas. 2005. Relationships between net
photosynthesis and foliar nitrogen concentrations in a loblolly pine forest ecosystem grown in
elevated atmospheric carbon dioxide . Tree Physiol , 25 (4): 385-394 .
We examined the effects of elevated carbon dioxide concentration ([CO2]) on the relationship
between light-saturated net photosynthesis (Asat) and area-based foliar nitrogen (N)
concentration (Na) in the canopy of the Duke Forest FACE experiment. Measurements of Asat and
Na were made on two tree species growing in the forest overstory and four tree species growing
in the forest understory, in ambient and elevated [CO2] FACE rings, during early and late summer
of 1999, 2001 and 2002, corresponding to years three, five and six of CO2 treatment. When
measured at the growth [CO2], net photosynthetic rates of each species examined in the forest
overstory and understory were stimulated by elevated [CO2] at each measurement date. We
found no effect of elevated [CO2] on Na in any of the species. The slope of the Asat—N
relationship was 81% greater in elevated [CO2] than in ambient [CO2] when averaged across all
sample dates, reflecting a differential CO2 effect on photosynthesis at the top and bottom of the
canopy. We compared Asat—N relationships in trees grown in ambient and elevated [CO2] at two
common CO2 concentrations, during late summer 2001 and both early and late 2002, to
determine if the stimulatory effect of elevated [CO2] on photosynthesis diminishes over time. At
all three sample times, neither the slopes nor the y-intercepts of the Asat—N relationships of
trees grown in ambient or elevated [CO2] differed when measured at common CO2
concentrations, indicating that the responses of photosynthesis to long-term elevated [CO2] did
not differ from the responses to a short-term increase in [CO2]. This finding, together with the
observation that Na was unaffected by growth in elevated [CO2], indicates that these overstory
and understory trees growing at the Duke Forest FACE experiment continue to show a strong
R. O. Teskey, H. L. Gholz, and W. P. Cropper, Jr. 1994. Influence of climate and fertilization on net
photosynthesis of mature slash pine . Tree Physiol , 14 (11): 1215-1227 .
Net photosynthesis was measured under field conditions in 23-year-old slash pine (Pinus elliottii
Engelm. var. elliottii) trees to determine how it was affected by fertilization and climate. There
was only a small decrease in rates of net photosynthesis from late summer through winter
demonstrating that appreciable carbon gain occurs throughout the year in slash pine. Although
fertilization substantially increased leaf area and aboveground biomass, it only slightly increased
the rate of net photosynthesis. Simultaneous measurements of gas exchange in fertilized and
unfertilized (control) plots allowed the detection of a small, but statistically significant difference
in average net photosynthesis of 0.14 μmol m−2 s−1. Irradiance, and to a lesser extent air
temperature, were the environmental factors that exerted the most control on net
photosynthesis. The highest rates of net photosynthesis occurred between air temperatures of
25 and 35 °C. Because air temperatures were within this range for 46% of all daylight hours
during the year, air temperature was not often a significant limitation. Soil and atmospheric
water deficits had less effect on photosynthesis than irradiance or air temperature. Although the
depth to the water table changed during the year from 10 to 160 cm, predawn and midday
xylem pressure potentials only changed slightly throughout the year. Predawn values ranged
from –0.63 to –0.88 MPa in the control plot and from –0.51 to –0.87 MPa in the fertilized plot
and were not correlated with water table depth. There was no correlation between xylem
pressure potentials and net photosynthesis, presumably because water uptake was adequate.
Although vapor pressure deficits reached 3.5 kPa during the summer, they had little effect on
net photosynthesis. Over a vapor pressure deficit range from 1.0 to 3.0 kPa, net photosynthesis
Kundu, S. K. dan P. M. A. Tigerstedt. 1999. Variation in net photosynthesis, stomatal
characteristics, leaf area and whole-plant phytomass production among ten provenances of
neem (Azadirachta indica) . Tree Physiol., 19 (1): 47-52 .
Variation in net photosynthesis, CO2 exchange parameters, stomatal characteristics,
leaf area and seedling dry weight were investigated among 10 provenances of neem
(Azadirachta indica A. Juss.) (Kundu dan Tigerstedt, 1999). Significant provenance
variation was established for net photosynthesis (8.14 to 15.13 μmol m−2 s−1), stomatal
conductance (0.37 to 0.59 mol m−2 s−1), stomatal density (145 to 204 mm−2), and total
guard cell length (2681 to 3873 μm). Net photosynthesis was positively correlated with
whole-plant dry weight and leaf area. Stomatal density was positively correlated with
net photosynthesis, whole-plant dry weight, and leaf area. Total guard cell length was
positively correlated with all of these traits. Information on six traits was used in a
cluster analysis to construct a dendrogram to assess phenetic relationships among the
provenances. With a few exceptions, the dendrogram revealed three major clusters
grouped according to rainfall distribution. The whole plant phytomass production of
neem seedlings was associated with photosynthesis and stomatal characteristics
during the early stages of growth.
. Thijs L. Pons and Rob A. M. Welschen. 2003. Midday depression of net photosynthesis in the
tropical rainforest tree Eperua grandiflora: contributions of stomatal and internal conductances,
respiration and Rubisco functioning. Tree Physiol. , 23 (14): 937-947
High midday temperatures can depress net photosynthesis. We investigated possible
mechanisms underlying this phenomenon in leaves of Eperua grandiflora (Aubl.) Benth.
saplings. This tropical tree establishes in small gaps in the rainforest canopy where direct
sunlight can raise midday temperatures markedly. We simulated this microclimate in a growth
chamber by varying air temperature between 28 and 38 °C at constant vapor pressure. A
decrease in stomatal conductance in response to an increase in leaf-to-air vapor pressure
difference (ΔW) caused by an increase in leaf temperature (Tleaf) was the principal reason for the
decrease in net photosynthesis between 28 and 33 °C. Net photosynthesis decreased further
between 33 and 38 °C. Direct effects on mesophyll functioning and indirect effects through ΔW
were of similar magnitude in this temperature range. Mitochondrial respiration during
photosynthesis was insensitive to Tleaf over the investigated temperature range; it thus did not
contribute to midday depression of net photosynthesis. Internal conductance for CO2 diffusion
in the leaf, estimated by combined gas exchange and chlorophyll fluorescence measurements,
decreased slightly with increasing Tleaf. However, the decrease in photosynthetic rate with
increasing Tleaf was larger and thus the difference in CO2 partial pressure between the
substomatal cavity and chloroplast was smaller, leading to the conclusion that this factor was
not causally involved in midday depression. Carboxylation capacity inferred from the CO2
response of photosynthesis increased between 28 and 33 °C, but remained unchanged between
33 and 38 °C. Increased oxygenation of ribulose-1,5-bisphosphate relative to its carboxylation
and the concomitant increase in photorespiration with increasing Tleaf were thus not
. Pierre Y. Bernier, F. Raulier, P. Stenberg, and Chhun-Huor Ung. 2001. Importance of needle age
and shoot structure on canopy net photosynthesis of balsam fir (Abies balsamea): a spatially
inexplicit modeling analysis. Tree Physiol . , 21 (12-13): 815-830.
We have developed a spatially inexplicit model of canopy photosynthesis for balsam fir (Abies balsamea(L.)
Mill.) that accounts for key processes of light–shoot interaction including irradiance interception by the
shoot, spatial aggregation of shoots into branches and crowns, the differential propagation of diffuse and
direct light within the canopy, and an ideal representation of penumbra. Also accounted for in the model are
the effects of the average radiative climate and shoot age on needle retention, light interception, and
photosynthetic capacity. We used reduced versions of this model to quantify the effects of simplifying
canopy representation on modeled canopy net photosynthesis. Simplifications explored were the omission
of direct beam transformation into penumbral light and the use of different constant shoot properties
throughout the canopy. The model was parameterized for a relatively dense balsam fir stand (leaf area index
of 5.8) north of Québec City, Canada, and run using hourly meteorological data obtained at the site. The
overall performance of the complete model was satisfactory, with maximum values of canopy net
photosynthesis of 23 μmol (m2 ground)−1 s−1 (83 mmol m−2 h−1), and a near-saturation of the canopy at a
photosynthetically active radiation photon flux density of about 750 μmol m−2 s−1 (2.7 mol m−2 h−1). The
omission of penumbral effects through the use of unattenuated direct (beam) radiation at all layers of the
canopy, as used for broad-leaved species, reduced canopy net photosynthesis by 3.7%. Analysis of the
results show that the small impact of penumbra on canopy net photosynthesis stems from the high
proportion of diffuse radiation (73%) estimated from our meteorological data set; single-hour results under
clear sky conditions approach theoretical bias values of about 30%. Use of mean shoot photosynthetic, light
capture and light transmission properties throughout the canopy biased canopy net photosynthesis by less
than 3%. However, simulations carried out based on properties of 1-year-old shoots throughout the canopy
overestimated canopy net photosynthesis by 9%. Use of the shoot as our smallest functional unit was a
potential source of bias because the differential absorption of direct and diffuse radiation within the shoot
could not be factored into the model. Other sources of potential bias are discussed.
. Stephen B. Horsley and K.W. Gottschalk. 1993. Leaf area and net photosynthesis during
development of Prunus serotina seedlings. Tree Physiol . , 12 (1): 55-69
We used the plastochron index to study the relationship between plant age, leaf age
and development, and net photosynthesis of black cherry (Prunus serotina Ehrh.)
seedlings. Leaf area and net photosynthesis were measured on all leaves ≥ 75 mm of
plants ranging in age from 7 to 20 plastochrons. Effects of plant developmental stage
on leaf area and net photosynthesis were evaluated for leaves of differing age
(horizontal series), leaves on plants of constant age (vertical series), and leaves of
constant age (oblique series). Regression techniques were used to estimate leaf area
from leaf blade dimensions. The best equations for predicting leaf area had R2 values
of 0.991–0.992 and used linear or logarithmic functions of both leaf length and width.
Suitable, but less precise, equations with R2 values of 0.946–0.962 were developed
from either leaf length or leaf width. Leaf area development in black cherry seedlings
was similar to that in other indeterminate species. Leaves of young plants reached full
expansion at a lower leaf plastochron age than leaves of older plants. Maximum net
photosynthesis per unit leaf area occurred 2–3 plastochrons before full leaf expansion.
There was strong ontogenetic drift in net photosynthesis with leaf age; net
photosynthesis decreased as plant age increased in leaves of the same plastochron
age. Plots of the oblique series were particularly useful in providing information about
interaction effects.
Teskey, R.O., J. A. Fites, L. J. Samuelson dan B. C. Bongarten. 1986. Stomatal and nonstomatal
limitations to net photosynthesis in Pinus taeda L. under different environmental conditions .
Tree Physiol., 2 (1-2-3): 131-142 .
Net photosynthesis, transpiration and stomatal conductance of two-year-old Pinus
taeda L. seedlings were compared under various environmental conditions. Teskey, et
al. (1986) examined seedlings responses to air temperature, irradiance, ambient CO2
concentration, absolute humidity deficit and xylem pressure potential. The seedlings
exhibited little response to a wide range of absolute humidity deficits (7 to 16 g m−3)
and temperatures (20 to 35 °C), but were sensitive to changes in water deficit,
irradiance and CO2 concentration. Net photosynthesis and stomatal conductance were
linearly related under all of the environmental conditions measured. However, the gas
phase limitation to photosynthesis was generally small (20 to 30%).
The stomatal response was closely coupled to changes in photosynthesis, internal
limitations, rather than the rate of gaseous diffusion of CO2, were primarily responsible
for limiting photosynthesis.
Jeffrey D. Herrick and Richard B. Thomas. 2003. Leaf senescence and late-season net
photosynthesis of sun and shade leaves of overstory sweetgum (Liquidambar styraciflua) grown
in elevated and ambient carbon dioxide concentrations. Tree Physiol. , 23 (2): 109-118 .
We examined the effects of elevated CO2 concentration ([CO2]) on leaf demography, late-season
photosynthesis and leaf N resorption of overstory sweetgum (Liquidambar styraciflua L.) trees in
the Duke Forest Free Air CO2 Enrichment (FACE) experiment. Sun and shade leaves were
subdivided into early leaves (formed in the overwintering bud) and late leaves (formed during
the growing season). Overall, we found that leaf-level net photosynthetic rates were enhanced
by atmospheric CO2 enrichment throughout the season until early November; however, sun
leaves showed a greater response to atmospheric CO2 enrichment than shade leaves. Elevated
[CO2] did not affect leaf longevity, emergence date or abscission date of sun leaves or shade
leaves. Leaf number and leaf area per shoot were unaffected by CO2 treatment. A simple shoot
photosynthesis model indicated that elevated [CO2] stimulated photosynthesis by 60% in sun
shoots, but by only 3% in shade shoots. Whole-shoot photosynthetic rate was more than 12
times greater in sun shoots than in shade shoots. In senescent leaves, elevated [CO2] did not
affect residual leaf nitrogen, and nitrogen resorption was largely unaffected by atmospheric CO2
enrichment, except for a small decrease in shade leaves. Overall, elevated [CO2] had little effect
on the number of leaves per shoot at any time during the season and, therefore, did not change
seasonal carbon gain by extending or shortening the growing season. Stimulation of carbon gain
by atmospheric CO2 enrichment in sweetgum trees growing in the Duke Forest FACE experiment
was the result of a strong stimulation of photosynthesis throughout the growing season.
Day, M.E. 2000. Influence of temperature and leaf-to-air vapor pressure deficit on net
photosynthesis and stomatal conductance in red spruce (Picea rubens) . Tree Physiol ., 20 (1):
57-63.
The roles of temperature (T) and leaf-to-air vapor pressure deficit (VPD) in regulating
net photosynthesis (Anet) and stomatal conductance (Gs) of red spruce (Picea rubens
Sarg.) were investigated in a field study and in a controlled environment experiment
(Day, 2000 ). Both Anet and Gs exhibited a relatively flat response to temperatures
between 16 and 32 °C. Temperatures between 32 and 36 °C markedly decreased both
Anet and Gs. Vapor pressure deficits above 2 kPa had significant effects on both Anet and
Gs. The influence of VPD on Anet and Gs fit a linear response model and did not interact
significantly with T effects.
. P. Harley, A. Guenther, and P. Zimmerman. 1996. Effects of light, temperature and canopy
position on net photosynthesis and isoprene emission from sweetgum (Liquidambar styraciflua)
leaves. Tree Physiol . , 16 (1-2): 25-32.
In June 1993, net photosynthetic rates, stomatal conductance and isoprene emission
rates of sweetgum leaves (Liquidambar styraciflua L.) were measured at the top of the
forest canopy (sun leaves) and within the canopy at a height of 8–10 m above ground
level (shade leaves). Large differences in net photosynthetic rates and stomatal
conductance were found between sun and shade leaves. Mean rates of isoprene
emission, expressed on a leaf area basis, were significantly lower in shade leaves than
in sun leaves (4.1 versus 17.1 nmol m−2 s−1); however, because specific leaf area of sun
leaves was lower than that of shade leaves (0.0121 versus 0.0334 m2 g−1), the
difference between sun and shade leaves was less, though still significant, when
isoprene emissions were expressed on a dry mass basis (45.5 versus 29.0 μg C g−1 h−1).
Saturation of both net photosynthesis and isoprene emission occurred at lower PPFDs
in shade leaves than in sun leaves. The effect of leaf temperature on isoprene
emissions also differed between sun and shade leaves. Sun leaves lost a significantly
greater percentage of fixed carbon as isoprene than shade leaves. The leaf-level
physiological measurements were used to derive parameters for a canopy-level
isoprene flux model. The importance of incorporating differences between sun- and
shade-leaf properties into existing models is discussed.
. Yoshiyuki Miyazawa and
Kihachiro Kikuzawa
Physiological basis of seasonal trend in leaf photosynthesis of five evergreen broad-leaved
species in a temperate deciduous forest Tree Physiol (2006) 26 (2): 249-256
he physiological basis of photosynthesis during winter was investigated in saplings of
five evergreen broad-leaved species (Camellia japonica L., Cleyera japonica Thunb.,
Photinia glabra (Thunb.) Maxim., Castanopsis cuspidata (Thunb.) Schottky and Quercus
glauca Thunb.) co-occurring under deciduous canopy trees in a temperate forest. We
focused on temperature dependence of photosynthetic rate and capacity as important
physiological parameters that determine light-saturated rates of net photosynthesis at
low temperatures during winter. Under controlled temperature conditions, maximum
rates of ribulose bisphosphate carboxylation and electron transport (Vcmax and Jmax,
respectively) increased exponentially with increasing leaf temperature. The
temperature dependence of photosynthetic rate did not differ among species. In the
field, photosynthetic capacity, determined as Vcmax and Jmax at a common temperature
of 25 °C (Vcmax(25) and Jmax(25)), increased until autumn and then decreased in speciesspecific patterns. Values of Vcmax(25) and Jmax(25) differed among species during winter.
There was a positive correlation of Vcmax(25) with area-based nitrogen concentration
among leaves during winter in Camellia and Photinia. Interspecific differences in
Vcmax(25) were responsible for interspecific differences in light-saturated rates of net
photosynthesis during winter.
Radoglou, K. dan R.O. Teskey. 1997. Changes in rates of photosynthesis and respiration during
needle development of loblolly pine. Tree Physiol , 17 (7): 485-488 .
Net photosynthetic rates of developing foliage and one-year-old foliage of loblolly pine
(Pinus taeda L.) were measured under field conditions (Radoglou dan Teskey, 1997).
In the subsequent year, net photosynthesis and dark respiration rates of current-year
and one-year-old foliage were measured under controlled environmental conditions.
Loblolly pine foliage grows slowly, reaching its final size 3.5 to 4 months after bud
burst. Positive rates of net photosynthesis were recorded when the foliage was 13 and
18% of final length, in the controlled-environment and field study, respectively.
However, because of high rates of dark respiration during the initial growth period, a
positive diurnal carbon balance did not occur until foliage was about a third of final
length (40 days after bud burst). Two months after bud burst, when foliage was about
55% of final length, its photosynthetic capacity exceeded that of one year old foliage.
The highest rates of net photosynthesis were achieved when foliage was more than
90% fully expanded.
Koch, G.W., J.S. Amthor dan M. L. Goulden. 1994. Diurnal patterns of leaf photosynthesis,
conductance and water potential at the top of a lowland rain forest canopy in Cameroon:
measurements from the Radeau des Cimes . Tree Physiol , 14 (4): 347-360 .
Koch, Amthor dan Goulden (1994) measured diurnal patterns of leaf conductance, net
photosynthesis and water potential of five tree species were measured at the top of
the canopy in a tropical lowland rain forest in southwestern Cameroon. Access to the
40 m canopy was by a large canopy-supported raft, the Radeau des Cimes. The
measurements were made under ambient conditions, but the raft altered the local
energy balance at times, resulting in elevated leaf temperatures. Leaf water potential
was equal to or greater than the gravitational potential at 40 m in the early morning,
falling to values as low as –3.0 MPa near midday. Net photosynthesis and conductance
were typically highest during midmorning, with values of about 10–12 μmol CO2 m−2
s−1 and 0.2–0.3 mol H2O m−2 s−1, respectively. Leaf conductance and net photosynthesis
commonly declined through midday with occasional recovery late in the day.
Photosynthesis was negatively related to leaf temperature above midday air
temperature maxima. These patterns were similar to those observed in other
seasonally droughted evergreen communities, such as Mediterranean-climate shrubs,
and indicate that environmental factors may cause stomatal closure and limit
photosynthesis in tropical rain forests during the midday period.
M. E. Jach and R. Ceulemans
Effects of season, needle age and elevated atmospheric CO2 on photosynthesis in Scots pine
(Pinus sylvestris) Tree Physiol (2000) 20 (3): 145-157.
Five-year-old Scots pine (Pinus sylvestrisL.) seedlings were grown in open-top
chambers at ambient and elevated (ambient + 400 μmol mol−1) CO2 concentrations.
Net photosynthesis (A), specific leaf area (SLA) and concentrations of nitrogen (N),
carbon (C), soluble sugars, starch and chlorophyll were measured in current-year and
1-year-old needles during the second year of CO2 enrichment. The elevated CO2
treatment stimulated photosynthetic rates when measured at the growth CO2
concentration, but decreased photosynthetic capacity compared with the ambient CO2
treatment. Acclimation to elevated CO2 involved decreases in carboxylation efficiency
and RuBP regeneration capacity. Compared with the ambient CO2 treatment, elevated
CO2 reduced light-saturated photosynthesis (when measured at 350 μmol mol−1 in
both treatments) by 18 and 23% (averaged over the growing season) in current-year
and 1-year-old needles, respectively. We observed significant interactive effects of CO2
treatment, needle age and time during the growing season on photosynthesis. Large
seasonal variations in photosynthetic parameters were attributed to changes in needle
chemistry, needle structure and feedbacks governed by whole-plant growth dynamics.
Down-regulation of photosynthesis was probably a result of reduced N concentration
on an area basis, although a downward shift in the relationship between
photosynthetic parameters and N was also observed.
. Does growth temperature affect the temperature responses of photosynthesis and internal
conductance to CO2? A test with Eucalyptus regnans Tree Physiol (2008) 28 (1): 11-19
Internal conductance to CO2 transfer from intercellular spaces to chloroplasts (g i) poses a major
limitation to photosynthesis, but only three studies have investigated the temperature
dependance of gi. The aim of this study was to determine whether acclimation to 15 versus 30
°C affects the temperature response of photosynthesis and gi in seedlings of the evergreen tree
species Eucalyptus regnans F. Muell. Six-month-old seedlings were acclimated to 15 or 30 °C for
6 weeks before gi was estimated by simultaneous measurements of gas exchange and
chlorophyll fluorescence (variable J method). There was little evidence for acclimation of
photosynthesis to growth temperature. In seedlings acclimated to either 15 or 30 °C, the
maximum rate of net photosynthesis peaked at around 30 or 35 °C. Such lack of temperature
acclimation may be related to the constant day and night temperature acclimation regime,
which differed from most other studies in which night temperatures were lower than day
temperatures. Internal conductance averaged 0.25 mol m−2 s−1 at 25 °C and increased threefold
from 10 to 35 °C. There was some evidence that gi was greater in seedlings acclimated to 15
than to 30 °C, which resulted in seedlings acclimated to 15 °C having, if anything, a smaller
relative limitation due to gi than seedlings acclimated to 30 °C. Stomatal limitations were also
smaller in seedlings acclimated to 15 °C than in seedlings acclimated to 30 °C. Based on
chloroplast CO2 concentration, neither maximum rates of carboxylation nor RuBP-limited rate of
electron transport peaked between 10 and 35 °C. Both were described well by an Arrhenius
function and had similar activation energies (57–70 kJ mol−1). These findings confirm previous
studies showing gi to be positively related to measurement temperature.
Figueroa,J.A., H.M. Cabrera, C. Queirolo dan L.F. Hinojosa. 2010. Variability of water relations
and photosynthesis in Eucryphia cordifolia Cav. (Cunoniaceae) over the range of its latitudinal
and altitudinal distribution in Chile. Tree Physiol. , 30 (5): 574-585 .
Figueroa et al. (2010) during the summer of the year 2008 investigated variation in leaf water
and photosynthetic characteristics of Eucryphia cordifolia Cav. (Cunoniaceae) along its broad
latitudinal distribution in central south Chile (36° to 42° S). The latitudinal variation in water
potential (Ψw), water potential at saturation (Ψπsat), water potential at the turgor lost point
(Ψπtlp), stomatal density of the leaves, leaf nitrogen concentrations and photosynthetic light
response were studied in eight populations. The populations located in the northern region of
the distribution of E. cordifolia had the lowest leaf water potential. Osmotic potential at full
turgor was highest in the two southernmost populations and gradually decreased towards the
northernmost points. Similarly, osmotic potential at zero turgor was the lowest in the northern
population. The symplastic water content was lower in the two southernmost populations. The
highest net photosynthesis rate was recorded for plants in the populations of intermediate
distributions, and it was dependent on the precipitation and temperature gradient. The
northern populations, which are subject to the lowest precipitations, showed the lowest
stomatal densities, which were tightly linked with stomatal conductance variation. Therefore,
the variability of Amax was independent of stomatal density and conductance, so that the
northern populations, subject to environments with less water availability, presented higher
photosynthetic water use efficiency.
The leaf water relations, stomatal characteristics and photosynthetic rates of the leaf would vary
along its latitudinal gradient, helping to explain the ability of E. cordifolia trees to inhabit a
broad latitudinal and altitudinal range throughout the central south Chile.