May 2001 Progress Report to the
Applied Research Program Reclamation of Phosphate Mined Lands of the Florida Institute of Phosphate Research for the project
by
D. L. Rockwood, D. R. Carter, and J. A. Stricker
University of Florida
Project Justification and Description
About 116,000 acres of currently little used reclaimed phosphate mined lands in Polk County are crucial to the maintenance and expansion of commercial forestry in central Florida. Through an extraordinary collaboration with public and private partners, our project will identify and develop 1) superior trees and 2) appropriate management practices for three commercial tree crops: cypress , slash pine , and cottonwood . From 2000 to 2005, this project will also 3) document the productivities of superior genotypes of these species and 4) estimate their economic value.
Cypress development will collect seed from existing and additional select trees, propagate and test these seedlots, expand a seed orchard with these selections, and assess silvicultural options. Slash pine research will test hybrid families in comparison with improved north Florida families.
Cottonwood research will select clones for use on clay settling areas (CSA) and determine planting configuration and fertilization options for maximum growth. Utilizing data from this project’s and other appropriate studies, growth and yield models will be constructed for each species so that stand productivities can be predicted from age and site parameters. These models will be combined with price variability for mulchwood, energywood, pulpwood, and sawtimber to determine economic viability for each species.
Commercial plantings of cypress and cottonwood will supplement research studies. These plantings will employ establishment techniques and planting stock developed by research and will provide "real-world" estimates of productivity and costs for use in growth model development and economic modeling. The plantings will be large enough for operational harvests at the end of a rotation.
A Web site will describe the project and project personnel and disseminate project reports and educational information about growing trees on reclaimed phosphate land.
Accomplishments to Date
This project has utilized the facilities, services, and/or expertise of Kent Company, Cargill, PCS
Phosphate, Knight’s Sawmill, the Common Purpose Institute (CPI), Orlando/Orange County
(O/OC), Natural Resource Planning Services (NRPS), and Central Florida Lands and Timber
(CFL&T) for research and commercial activities to date. Kent, Cargill, PCS, and Knight’s provided study sites. CPI, O/OC, and NRPS assisted in site preparation and provision of study materials.

CFL&T conducted cypress seed collections, grew cypress seedlings, and managed a seed orchard.
These collaborations enhance awareness of the project’s objectives and increase the likelihood of commercialization.
Cypress research to develop improved planting stock and management practices utilized previously established tests and a seedling seed orchard and established new tests.
Remeasurement of tests established in 1996-97 indicated that nine baldcypress provenances and five baldcypress checklots were, on average, taller than 16 pondcypress progenies, but all were similar in survival after four years. Within taxa, individual provenance/progeny differences were significant, but no provenances or progenies were consistently better across sites that ranged from bottomland in northwest Florida to wet and dry flatwoods in northeast Florida to a fertile but poorly drained CSA in central Florida. Inconsistent topsoil redistribution hindered the growth through three years of 21 baldcypress and two pondcypress progenies planted on a reclaimed phosphate mine near White Springs in 1998. Bedding+compost on a good flatwoods site significantly increased the growth of 30 baldcypress progenies and four Florida pondcypress progenies compared to bedding alone in studies established in 1999 and 2000. In another flatwoods study planted in 2000, bedding+compost also resulted in better growth and survival than just bedding, which in turn was superior to no bedding. CFL&T’s intensively managed seed orchard established in December 1997 with 12 pondcypress progenies, nine baldcypress provenances, and three baldcypress clones produced cones in Fall 2000 on trees up to 5.2m tall.
Two new cypress genetics studies with 11 progenies (A, B, C, D, E, F, G, H, I, J, L) and two checklots (Baron, Local) of baldcypress, and one pondcypress progeny (K) were established on bedded CSAs, one at the Kent site east of Lakeland, the other at a Cargill site southwest of Ft.
Meade. Both studies have good early growth and survival.
Collectively, these seedlots and studies provide an excellent basis for selecting superior seedlots from the CFL&T orchard. Results to date show the potential for commercial cypress plantations on non-wetland sites for the production of mulchwood and sawtimber in rotations of 10 to 25 years.
To expand the project’s cypress genetic base population from the present nearly 100 accessions mostly from northern Florida, a seed collection was conducted from October through December.
Fifty new individual tree accessions well represent northeast Florida and are being grown along with some south Florida accessions and seed orchard progenies in CFL&T’s nursery for inclusion in new studies.
Slash pine research activities involved arranging for seedlots, designing the study, and preparing a site for the study. Seedlots of five hybrid taxa (12 per taxon) especially suited to central Florida climatic and edaphic conditions were arranged with the Queensland Forestry Research Institute;
12 very fast-growing north Florida seedlots were selected to represent genetically improved slash pine now available for commercial planting in the area. A split-, split-plot randomized complete block design involving three replications of taxa main plots and seedlots in 6-tree row subplots was developed for the study to be planted at the Kent site in December 2001. Bedding and herbiciding for the ~2,500 tree study were completed in April.

Cottonwood research studies established on the Kent CSA were a clone test, a cloneconfiguration-fertilizer study, and a clone nursery. The clone test compares 77 clones within a
Latin Square design consisting of three species main plots, four replications as subplots, and singletree subsub plots. One of the cottonwood main plots was felled in April to examine clonal differences in coppicing ability. The second study involves six of the 77 clones (Ken 8, S7C1,
S13C20, ST-240, -259, -261), two planting configurations (single or double rows per bed), and fertilizer levels (rates of ammonium nitrate) in a split-plot design with configuration main plots, species subplots, and clones in 6-tree row subsbuplots for a total of 960 trees including borders.
Spacing in both studies was 11' between beds, 3' between trees on a bed.
The clone nursery contains 13 promising clones for central Florida: Ken 8, S7C1, S13C20, ST-66,
-70, -72, -124, -148, -163, -240, -244, -259, -261. The approximately 1,000 ramets of each clone that were planted have the potential for annually producing 10,000 unrooted stem cuttings for future plantings, or 130,000 from the whole nursery.
Commercial plantings of cypress and cottonwood, 71 and 10 acres in size, respectively, were established to supplement yields estimated in the project’s research studies. About 45,000 potted trees of 10 of the 14 cypress seedlots in the newest research studies were planted at 10x7' spacing on three site types following CSA reclamation at Cargill: 40 acres of sand-clay mix
(FM03/04 - 7 bed strips of seedlots A, E, F, H, I, J, L, Local), 21 acres of sand over clay (FM06 -
7 row strips of seedlots A, B, C, F, H, I, J, L, Local), 10 acres of unbedded clay (FM06 - 7 row strips of seedlots B, E, F, H, I, L, Local) from April to May. The 10 acres of three cottonwood clones (mix of Ken 8, S7C1, S13C20) planted at 10x2.5' spacing on beds at the Kent site from
April to May have both single and double row configurations.
Development of the “Tree Crops for Phosphate Mined Lands” website has been initiated with an outline of site content, assembly of information about the project and project personnel, and tabulation of other websites to be linked.
Future Activities
Cypress activities will involve seed collections, seedling production, and test installation and measurement. A second cypress seed collection from approximately 100 individual trees in central and southern Florida will be completed in November 2001 for inclusion in test(s) to be installed in
Fall 2002. Tests and commercial plantings will be measured annually for size and survival starting
December 2001. Better performing seedlots will then be identified for collection from an existing seedling seed orchard, as possible. Preliminary site preparation and fertilization recommendations for rapid cypress growth should be available by the end of 2004.
Slash pine hybrid tests will also be measured annually for tree size and survival through the end of the project. New slash pine hybrids will be outplanted in December 2001, and the best hybrid seedlots in previous tests will be identified. In the last year of the project, the best new hybrid seedlots will be identified for commercial use, and sources of their commercial availability developed.
Cottonwood tests will be measured semiannually for tree size and survival beginning six months after planting and continuing through 2.5 years. In June 2002, initial recommendations on clones

for commercial use will be derived and will be revised annually thereafter based on growth, survival, tree quality characteristics, and coppicing success and growth. Superior clones will be entered into field clone banks or greenhouse hedges for cutting propagation as early as February 2002.
Prices and price variability for energywood, pulpwood, and sawtimber will be assessed by interviewing individuals and firms that are active in the area, starting in 2002. Production cost information will also be collected. Economic evaluation will use several economic indicators, including
1) land rent, 2) benefit/cost ratio, 3) equal annual annuity, and 4) internal rate of return. A simulation-based risk analysis will be conducted using a range of real discount rates and varying price and cost assumptions using specialized spreadsheet software. Optimal economic and biological rotation ages under all cases will be determined. A preliminary spreadsheet decision analysis program will be available in Year 4 and finalized in Year 5 for growing commercial tree crops on reclaimed phosphate land.
The “Tree Crops for Phosphate Mined Lands” website will be operational by September 2001 and will be updated quarterly.
Cottonwood at the Kent site will be observed by about 35 people attending the 5 th Biomass
Conference of the Americas n Orlando during the Short Rotation Woody Crops Production and
Utilization Technical Tour on September 21, 2001.
Publications
Stricker, J. A., G. R. Alker, D. L. Rockwood, G. M. Prine, and S. A. Segrest. 2000. Short rotation woody crops for Florida. In: Proc. Short Rotation Woody Crops Operations Working Group,
October 11-13, 2000, Syracuse, NY.
Prine, G. M., and D. L. Rockwood. 2000. Many short rotation trees and herbaceous plants available as energy crops in humid lower South. In: Proc. Bioenergy 2000, October 15-19, 2000.
Buffalo, NY.
Alker, G. R., Rockwood, D. L., L. Q. Ma, and A. E. S. Green. 2000. Phytoremediation and bioenergy production systems in Florida using fast growing tree species. In: Proc. Florida
Remediation Conference, November 15-19, 2000, Orlando, FL.
Rockwood, D. L. 2001. Performance of Queensland produced slash x Caribbean pine hybrids in peninsular Florida. In Cooperative Forest Genetics Research Program 43rd. Prog. Rpt. p. 4-6.
Rockwood, D. L., G. R.Alker, and R. W. Cardellino. 2000. Forest trees for land reclamation and remediation. In: Proc. Natural Resources Forum, June 19-21, 2001, Tampa, FL. (In press)
Rockwood, D. L., D. M. Morse, and L. T. Gaviria. 2001. Genetic and silvicultural factors affecting productivity of planted cypress in Florida. In: Proc. 26th South. For. Tree Improvement Conf.,
June 26-29, 2001, Athens, GA. (in preparation)
Land, S. B., Jr., Rockwood, D. L., M. Stein, G. R. Alker, M. V. Warwell, and X. Ma. 2001. A tree

improvement program for eastern cottonwood in the southeastern United States. In: Proc. 26th
South. For. Tree Improvement Conf., June 26-29, 2001, Athens, GA. (in preparation)
Rockwood, D. L., and G. R. Alker. 2001. Cottonwood clones for dendroremediation in Florida.
Florida Coop. Exp. Serv. (in preparation)
Segrest, S. A., D. L. Rockwood, J. A. Stricker, and G. R. Alker. 2001. Partnering to cofire woody biomass in central Florida. In: Proc.5
th Biomass Conference of the Americas, September 17-21,
2001, Orlando, FL. (in preparation)
Presentations
Stricker, J. A. 2000. Short rotation woody crops for Florida. Short Rotation Woody Crops
Operations Working Group, October 11-13, 2000, Syracuse, NY.
Alker, G. R. 2000. Phytoremediation and bioenergy production systems in Florida using fast growing tree species. Florida Remediation Conference, November 15-19, 2000, Orlando, FL.
Rockwood, D. L. 2001. Forest trees for land reclamation and remediation. Natural Resources
Forum, June 20, 2001, Tampa, FL. (in preparation)
Morse, D. M. 2001. Genetic and silvicultural factors affecting productivity of planted cypress in
Florida. 26th South. For. Tree Improvement Conf., June 26-29, 2001, Athens, GA. (in preparation)
Rockwood, D. L. 2001. Partnering to cofire woody biomass in central Florida. 5
Conference of the Americas, September 17-21, 2001, Orlando, FL. (in preparation) th Biomass
Rockwood, D. L., J. A. Stricker, and S. A. Segrest. 2001. Short Rotation Woody Crops Production and Utilization Technical Tour. 5 th Biomass Conference of the Americas, September 21, 2001,
Orlando, FL. (in preparation)