An Overview of the Plantation Management Research Cooperative

(PMRC)1975-2003

Barry D. Shiver

Director

Creation of the PMRC• Began as an attempt to develop better

management methods for plantations

• Originally begun in flatwoods of GA and FLA since plantations were older there

• UGA School of Forest Resources hired students to measure growth and yield plots in summer 1975

• First 5 year MOA 1976-1980

Original Ten Members:

• Brunswick Pulp Land Company

• Continental Can• Container Corporation• Gilman Paper

Company• Hudson Pulp & Paper

• ITT Rayonier• Owens Illinois• St. Regis• St. Joe Paper

Company• Union Camp

Objectives:• Improve stand level management through

use of well designed, statistically sound silvicultural studies– Emphasis was on regional importance and

therefore replication was minimized at site level

• Improve forest level management through development of better growth and yield models to use in harvest scheduling– Models would incorporate findings of

silvicultural studies

Replication

• Our ideas on replication at a location are different from those at other institutions who base their ideas on traditional Ag experimental designs

• There is much more variation across our landscapes than within our stands so we want to capture as much of that variation as possible

Replication• We are not so concerned with making the right

decision within the stand where we have an experiment

• We are more concerned with having enough replication (# of installations) across the landscape to confidently make decisions on differences regionally

• There are valid reasons for replication at a site for some objectives, but management decisions across the landscape is not one of them

Slash Pine Growth and Yield• Began with the 1975 data from several

hundred growth and yield plots• Diameter distribution models based on

Weibull• In 1976 the plots were revisited and trees

were cut and sectioned– Weight, Volume, and Taper Equations– Site index equations from stem analysis data

• Result was a yield system for site prepared plantations

Cronartium Study• First PMRC designed study

• In 1976 student crews installed about 200 plots in stands across a gradient of ages, site qualities, and infection levels

• Location of cronartium cankers along with their size, shape, etc. were noted on each infected tree plus dbh, ht, crown class, etc.

• Plots were remeasured every 3 years until the study was terminated

Cronartium Study

• Mortality functions with fusiform rust infection as a variable were developed

• Effect of cronartium on individual tree growth was modeled

Loblolly Growth and Yield

• Some loblolly plots were measured in 1975 though most plantations were too young

• In 1977 PMRC student crews measured several hundred loblolly plots in the Carolina’s and felled trees as they went to obtain a dataset similar to the slash dataset

• Loblolly volume, weight, taper, diameter distribution and site index models were developed

Competing Vegetation Study

• In 1977 the 42 slash pine competing vegetation study installations were established

• Paired plots to evaluate effect of understory vegetation on 10-12 year old slash pine

• Study was measured every 2 years for over 14 years

• Documented the yield reduction from understory competing vegetation

Slash Pine Control Plot

Slash Pine Treatment Plot

Slash Pine Site Preparation Study• Study to evaluate effects of mechanical site

preparation on slash pine growth and yield• Initiated in 1978• Included 4 complete vegetation control

plots and fertilization on all treatments except check

• This study is still yielding valuable information today

• Included one treatment to duplicate previous treatment

Thinning Studies

• Union Camp and St. Regis donated a large set of remeasured studies 12-17 years old that had been designed as a thinning study

• The design called for unthinned plots at different densities and larger plots that were to be thinned to the number remaining on the unthinned plots

• PMRC student crews thinned and measured the plots in 1978

Thinning Studies

• The unthinned thinning plots have been used to develop mortality functions

• The thinned plots were used to develop thinning responses for growth and yield models

• Our thinned models are based on an unthinned counterpart– This is a useful response model because it

allows us to develop thinning models from unthinned stands and plots

Species Comparison• Slash and loblolly were planted side by side on

160 locations across 8 soil groups• Objective was to determine where loblolly should

be planted and where slash should be planted• Half installed in 1979 and half in 1980• Loblolly was as productive as slash on all sites

and was more productive on several sites• Study was remeasured through age 20

Study has now been terminated

Remeasurement

• In 1980 both the slash and loblolly growth and yield plots were remeasured

• Allowed for development of – Mortality functions– Basal area projection equations– Height-Age curves based on remeasured rather

than stem analysis data

New MOA• As part of the new 5 year MOA a new geographic

subgroup was added – the SAGS (South Atlantic Gulf Slope) group was added

• Many companies operated in both areas• Emphasis for this 5 year period was on

maintaining and measuring existing studies in flatwoods and beginning new studies in SAGS region

SAGS studies

• SAGS region growth and yield plots including felled trees for volume, weight, and taper determination

• In 1984 a SAGS version of the competing vegetation study was established in loblolly stands– Loblolly was found to respond even more than

slash pine to removal of understory vegetation

SAGS studies• In 1986 a loblolly pine site preparation study with

28 locations was established• Objective was to quantify the effect of differing

site preparation treatments on survival, growth and yield

• This study included a complete vegetation control plot, but no fertilization

• Some treatments mirrored the operational treatments of the day very well

• The study was fertilized at age 12 and is ongoing

Chop, Burn

Shear, Rake, and Disk

Brown & Burn

Complete Vegetation Control

Improved Planting Stock/Vegetation Control Studies• Otherwise known as Herb-Gen Studies

• Loblolly established in 1986

• Objective was to evaluate effect of improved genetic stock in block plantings and to determine the interaction of improved stock and vegetation control treatments

Herb Gen• Loblolly is two studies – one for coastal plain and

one for piedmont• Different families involved and completely

separate analysis• Genetics in study is for rogued first generation

orchards• No longer planting this, but the type of response

we get helps us model newer genetics with information from progeny tests (additive response)

• We want to evaluate the type of response over a rotation length

Herb Gen

• Response for the herb gen plots has been very consistent across geographic regions for loblolly and even for slash pine

• Get a response for improved genetics and a response for vegetation control and the two repsonses are additive

• Get a reduction in cronartium infection for both species even with faster growth

Bulk Lot, No Veg Cntl - Age 13

Unimproved, Veg Cntl - Age 13

Bulk Lot, Veg Cntl - Age 13

A Mid 80’s Change

• In the mid 1980’s the University hired permanent staff to work on PMRC and other long term research projects

• Having permanent staff to visit research installations for maintenance and measurement insured better consistency from company to company

• It also facilitated data turnaround from measurement to analysis to report

Permanent Field Staff

• We now have 6 workers who maintain and measure PMRC, CAPPS, and other research plots for the University

• The professionalism exhibited by these crews has allowed PMRC to maintain plot numbers that we not would otherwise have been able to maintain

Culture Density Studies

• Realized that our density studies probably provided incorrect answers for intensively managed stands

• One location spacing study at B.F. Grant indicated our ideas on density were incorrect

• Established in SAGS region in 1995 and in Coastal Plain in 1996

• 2 levels of management and 6 densities

Culture Density Studies

• Several coastal plain sites have slash and loblolly at 300, 900, and 1500 tpa so there is opportunity for species comparison at 2 levels of management

• Through age 6 some loblolly trees are growing at 7 ft/yr and the average is over 5 ft

• Intensive culture impacts height growth on loblolly more so than on slash pine

• Basal areas are 140-175 ft2/ac at age 6 for higher densities (>1200 tpa)

BF Grant Spacing Study - 200 TPA

BF Grant Spacing Study - 1000 TPA

Intensively Managed loblolly pine - 6 yrs old, 300 tpa planted

Intensive lob – 6 yrs; 600 tpa planted

Intensive lob – 6 yrs; 900 tpa planted

Intensive lob – 6 yrs; 1200 tpa planted

Intensive Culture/Density Study - Slash Age 2

Growth and Yield Models

• Much more sophisticated than earlier efforts• Now we combine growth and yield plots with

designed study results• We have models for first generation plantations

and second generation plantations• We have the ability to estimate effects of multiple

silvicultural treatments (hardwood control, herbaceous weed control, fertilization)

Slash and Loblolly PineGrowth and Yield Systems:

• Whole stand system with merchandising component

• Diameter distribution

• Generalized stand table projection

• Response models for intensive management treatments

PMRC Studies as Research Platforms

• Throughout the history of the PMRC the study sites have been used for research purposes for which they were not originally intended when that could be accomplished without compromising the original intent

• Slash site preparation studies have been used to evaluate nutrient cycling and wood quality

PMRC Studies as Research Platforms

• The herb gen plots have been used by the wood quality consortium as have the species comparison plots

• The intensive culture/density studies have been used for a variety of leaf area, biomass and physiology studies

• Larger scale studies like these have been submitted for funding to national agencies

PMRC Studies as Research Platforms

• The intensive culture/density studies are also the research platform for the branch modeling study recently funded (partially) by TIP3

• So, in addition to the good management and modeling information PMRC gets, these plots serve as a basis for funding from other agencies (Agenda 2020,NRI, TIP3, etc.)

Conclusions

• So, after 28 years, the PMRC and other cooperatives have served the forestry community well

• They have done so by taking the long term view. If coops do not maintain long term studies, who will?

• As you and your company representatives ponder the future of forestry research, take a long term view

Conclusions

• Many of the useful results that govern our current silvicultural and management systems, the underlying study, even if it was funded outside a cooperative, was a coop study

• For those who never knew some of the old studies established by PMRC, come up with some new ways of using that old data and let us know!