Overview
Objectives
The primary objective of this study is to examine how the differing crown attributes produced by three clonal varieties and one family of loblolly pine (Pinus taeda) affect forest growth, biomass distribution, and stand dynamics. Here we report the contrast for two Clones: A and B
A secondary objective is to examine how these crown attributes correspond to the thinning response of the different genotypes.
Summary / Lessons Learned / Additional Thoughts
Two clones differed in their crown characteristics. Clone B added more height and had a cleaner (no branches) bole under narrow spacing than clone A. This suggests genetics could be used to select for desirable traits but the effect may depend on tree spacing.
Future reporting will include updates on the thinning response of the two clones. Clone A has a larger crown than Clone B, suggesting it will respond more to thinning.
Long Description of Practice
The previous slash pine plantation (established approximately in 2002) was whole-tree harvested in 2009. Prior to this harvest, the site was treated with glyphosate herbicide (Makaze, 5.2 dm3 ac-1, 2 quart ac-1) with a surfactant (Li700, 0.585 l ha-1, 8 oz ac-1).
The trees were treated with 36.8% permethrin at a rate of 1.9 liters (2 quarts) per 100,000 individuals just prior to planting. The study site was hand-planted with containerized seedlings in February 2010. Genetic entries consisted of three loblolly pine clones (Clone A, Clone B, and Clone C) derived from somatic embryogenesis, and a loblolly pine full-sib seedling family (Family B) (see notes on data collection process below for plot design specifics).
For the three years after planting, weed competition was treated as needed with glyphosate (5%), sulfometuron methyl (Sulfomet XP, 0.11 l ha-1,1.5 oz ac-1), clopyralid Sp (Transline, 1.17 l ha-1, 16 oz ac-1), and mowing. This kept the understory relatively free of vegetation while the overstory developed. In April 2010, trees were treated with fipronil (PTM, 1 ml chemical + 9 ml water per tree injected into root zone) to protect against infestation by Nantucket pine tip moth (Rhyacionia frustrana (Comstock)). In May 2010, any dead trees were replaced with the same genotype from extra trees stored on site in container racks. In September 2011, the entire experiment was broadcast fertilized with 535 kg ha-1 of a 10-10-10 + micronutrient blend with 0.05% Mn, 0.07% Zn, 0.17% Fe, 0.02% Cu, and 0.02% B.
Results
Tree Diameters Table
| Date (month / year) | Species | ||
|---|---|---|---|
Tree Heights Table
| Date (month / year) | Species | |||
|---|---|---|---|---|
Volume Table
| Date (month / year) | Species | ||
|---|---|---|---|
Other Table
| Date (month / year) | Species | Clone | Spacing (ft) Narrow=6 x 12 Wide = 12 x 12 | DBH (in) | Height (ft) | Ht. to Base of Live crown |
|---|---|---|---|---|---|---|
| 3/2021 (age 10) | Loblolly pine | A | Narrow | 7.3 | 47.9 | 24.0 |
| 3/2021 (age 10) | Loblolly pine | A | Wide | 8.6 | 51.2 | 24.0 |
| 3/2021 (age 10) | Loblolly pine | B | Narrow | 7.2 | 59.4 | 26.2 |
| 3/2021 (age 10) | Loblolly pine | B | Wide | 8.2 | 46.9 | 20.3 |
Study Location / Installation Information
Lattitude
Longitude
Accessibility
Landowner HAS consented to property visits WITH PERMISSION
Who installed study
First name: Tim
Last name: Martin
Year of installation
2010
Does study have end date
NO
Planned or actual end date
Information not provided.
Contact for access
Is study monumented
NO
Photos
Stand Information Pretreatment
Land Use History
The study site was previously a slash pine (Pinus elliottii) plantation that had been growing for 7 years before being whole-tree harvested in 2009. That was itself preceded by at least 10 years of horticultural crop experiments.
Stand Area
Information not provided.
Stand Age Before Treatment
7 Years Old
Pretreatment Overstory Community Composition
Slash pine (Pinus elliottii)
Pretreatment Forest Metrics
Total Basal Area
Information not provided.
Species Composition
Information not provided.
Soil Series
Pomona (Spodosol), Millhopper (Ultisol), and Pelham (Ultisol) series. While the Pomona and Pelham series are classified as poorly drained, and Millhopper well-drained, the site has been ditched and there has been no indication (e.g., standing water, ground vegetation) of differences in soil moisture across the study area.
Silvicultural Application(s) Used in Study
What did the study investigate?
- Other
Other Investigations
Genetics (Clonal and family variation)
If silviculture included a harvest, what type(s)?
Information not provided.
Silvicultural Action(s) Timings and Types / Intensities
Information not provided.
Are there any local forest health threats to your target species?
Yes
Notes on silvicultural process(es) or data collection
Plans for Future Treatments
'To-be-thinned' plots were thinned. This data will be added to a future report.
Only the significant contrast for Clone A and B are shown in this report.
Plans for Future Measurements
Future measurements in this trial will enable us to examine how different varieties respond to thinning; how previously-observed differences in crown dimensions and growth responses are affected by thinning; whether different varieties begin self-thinning at different relative densities; and other stand dynamics and competition topics.
One prediction associated with narrow-crowned crop ideotypes is that they might have increased carrying capacity or stockability, possibly realized through increased individual tree resource efficiency and an associated potential to carry higher relative density (At age 10 years, the narrow spacing treatments in the current study had just reached relative density consistent with the onset of density-dependent mortality). The study was subsequently thinned at age 11, and so at the time of writing contains a wide range of relative density conditions, from free-to-grow to experiencing density-dependent mortality, conditions favorable for testing the stockability of clones across this gradient.
Costs and Economic Considerations
These were not tracked as it was an experiment, but the number of treatments associated with this installation would make it on the higher end of cost for a plantation. One cost savings is planting in an old-field which reduced the site preparation costs.
Scientific Study Information
Is this study published?
No
Study Design
Split-split plot, randomized complete block
Number of Replicates
3
Size of Plots
3 Acres
Planting Density
Information not provided.