scholarly journals Douglas-Fir Biomass Allocation and Net Nutrient Pools 15–20 Years after Organic Matter Removal and Vegetation Control

Forests ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 1022
Author(s):  
K. M. Littke ◽  
T. B. Harrington ◽  
S. M. Holub ◽  
W. R. Littke ◽  
R. B. Harrison ◽  
...  
Keyword(s):  
Organic Matter ◽  
Biomass Allocation ◽  
Douglas Fir ◽  
Soil Productivity ◽  
Soil Base ◽  
Nutrient Pools ◽  
Vegetation Control ◽  
Old Trees ◽  
Whole Tree

Douglas-fir (Pseudotsuga menziesiivar. menziesii (Mirbel) Franco) plantation forests of the coastal Pacific Northwest have been intensively managed to improve the yield of forest products. However, the long-term effects of these management techniques have received limited research attention in this region. Three affiliate Long-Term Soil Productivity study sites were installed in Douglas-fir forests to understand the impacts of organic matter removals and vegetation control on soil productivity over time. Matlock and Fall River are located in Washington, USA and Molalla is located in Oregon. Organic matter removal treatments included traditional bole-only harvest (BO), whole tree removals (WT), and a whole tree plus coarse woody debris removal (WT+) (Fall River only). Five years of annual vegetation control (AVC) was compared with a conventional initial vegetation control (IVC) treatment at all sites. Douglas-fir biomass allocation to foliage, branch, and stem components was modeled using 15- to 20-year-old trees from this study along with 5- to 47-year-old trees from previous studies on these sites. Across all sites, model predictions indicated that the WT treatment had 7.1 to 9.7 Mg ha−1 less Douglas-fir biomass than the BO treatment. There was 1.5 to 20.5 Mg ha−1 greater Douglas-fir biomass in the AVC treatment than in the IVC treatment at all sites. Douglas-fir carbon and nitrogen biomass were consistently lower in the WT treatment, but there were no significant changes in overall site nutrient pools. The AVC treatment resulted in greater Douglas-fir nutrient pools yet there was a net loss in site calcium, magnesium, and potassium due to lower forest floor and soil base cation pools. While WT removals did not significantly affect site nutrition, the decrease in Douglas-fir biomass at all sites and increase in invasive Scotch broom (Cytisus scoparius (L.) Link) biomass at Matlock suggests that the standard practice of retaining harvest residuals is beneficial. The use of intensive vegetation control to improve Douglas-fir biomass and nutrition must be balanced with retaining soil base cations.

Effects of organic matter removal, soil compaction, and vegetation control on 5-year seedling performance: a regional comparison of Long-Term Soil Productivity sites

2006 ◽  
Vol 36 (3) ◽  
pp. 529-550 ◽  
Author(s):  
Robert L Fleming ◽  
Robert F Powers ◽  
Neil W Foster ◽  
J Marty Kranabetter ◽  
D Andrew Scott ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Compaction ◽  
Forest Floor ◽  
Soil Productivity ◽  
Individual Tree ◽  
Seedling Performance ◽  
Organic Matter Removal ◽  
Vegetation Control ◽  
Wide Range

We examined fifth-year seedling response to soil disturbance and vegetation control at 42 experimental locations representing 25 replicated studies within the North American Long-Term Soil Productivity (LTSP) program. These studies share a common experimental design while encompassing a wide range of climate, site conditions, and forest types. Whole-tree harvest had limited effects on planted seedling performance compared with the effects of stem-only harvest (the control); slight increases in survival were usually offset by decreases in growth. Forest-floor removal improved seedling survival and increased growth in Mediterranean climates, but reduced growth on productive, nutrient-limited, warm–humid sites. Soil compaction with intact forest floors usually benefited conifer survival and growth, regardless of climate or species. Compaction combined with forest-floor removal generally increased survival, had limited effects on individual tree growth, and increased stand growth in Mediterranean climates. Vegetation control benefited seedling growth in all treatments, particularly on more productive sites, but did not affect survival or alter the relative impact of organic matter removal and compaction on growth. Organic matter removal increased aspen coppice densities and, as with compaction, reduced aspen growth.

Effects of forest soil compaction and organic matter removal on leaf litter decomposition in central British Columbia

1999 ◽  
Vol 79 (4) ◽  
pp. 543-550 ◽  
Author(s):  
J. M. Kranabetter ◽  
B. K. Chapman
Keyword(s):  
British Columbia ◽  
Organic Matter ◽  
Litter Decomposition ◽  
Soil Compaction ◽  
Soil Productivity ◽  
Decomposition Rates ◽  
Nutrient Translocation ◽  
Organic Matter Removal ◽  
Whole Tree

As part of the long-term soil productivity study in central British Columbia, we examined the effect of soil compaction and organic matter removal on trembling aspen (Populus tremuloides Michx.) litter decomposition. We compared three levels of organic matter removal (stem-only, whole-tree harvest, and scalped mineral soil) and two levels of compaction (no compaction and heavy compaction) in a factorial design replicated as blocks on three sites. Whole-tree harvesting significantly increased litter decomposition rates compared to stem-only (by 36%) and scalped (by 41%) treatments. Soil compaction had inconsistent effects on decomposition rates (k) for forest floor and scalped treatments and, overall, did not significantly affect litter decomposition rates. Litter on scalped plots had higher rates of nutrient translocation than litter on forest floors. We found the treatments altered soil heat sums, so changes in temperatures at the soil surface might be partly responsible for the changes in decomposition rates. We could not detect differences in soil mesofauna populations collected from the litter bags, so treatment effects on fauna probably had less influence than microclimate on decomposition rates. The effects of these early changes in litter decomposition on biological productivity will be part of the ongoing long-term soil productivity study. Key words: Litter decomposition, soil compaction, scalping, whole-tree harvest, nutrient translocation

Soil organic matter in rainfed cropping systems of the Australian cereal belt

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 435 ◽  
Author(s):  
R. C. Dalal ◽  
K. Y. Chan
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Management Practices ◽  
Performance Indicator ◽  
Annual Rainfall ◽  
Soil Productivity ◽  
Organic C ◽  
Soil C ◽  
Eastern Australia

The Australian cereal belt stretches as an arc from north-eastern Australia to south-western Australia (24˚S–40˚S and 125˚E–147˚E), with mean annual temperatures from 14˚C (temperate) to 26˚C (subtropical), and with annual rainfall ranging from 250 mm to 1500 mm. The predominant soil types of the cereal belt include Chromosols, Kandosols, Sodosols, and Vertosols, with significant areas of Ferrosols, Kurosols, Podosols, and Dermosols, covering approximately 20 Mha of arable cropping and 21 Mha of ley pastures. Cultivation and cropping has led to a substantial loss of soil organic matter (SOM) from the Australian cereal belt; the long-term SOM loss often exceeds 60% from the top 0–0.1 m depth after 50 years of cereal cropping. Loss of labile components of SOM such as sand-size or particulate SOM, microbial biomass, and mineralisable nitrogen has been even higher, thus resulting in greater loss in soil productivity than that assessed from the loss of total SOM alone. Since SOM is heterogeneous in nature, the significance and functions of its various components are ambiguous. It is essential that the relationship between levels of total SOM or its identif iable components and the most affected soil properties be established and then quantif ied before the concentrations or amounts of SOM and/or its components can be used as a performance indicator. There is also a need for experimentally verifiable soil organic C pools in modelling the dynamics and management of SOM. Furthermore, the interaction of environmental pollutants added to soil, soil microbial biodiversity, and SOM is poorly understood and therefore requires further study. Biophysically appropriate and cost-effective management practices for cereal cropping lands are required for restoring and maintaining organic matter for sustainable agriculture and restoration of degraded lands. The additional benefit of SOM restoration will be an increase in the long-term greenhouse C sink, which has the potentialto reduce greenhouse emissions by about 50 Mt CO2 equivalents/year over a 20-year period, although current improved agricultural practices can only sequester an estimated 23% of the potential soil C sink.

Effects of logging debris treatments on five-year development of competing vegetation and planted Douglas-fir

2010 ◽  
Vol 40 (3) ◽  
pp. 500-510 ◽  
Author(s):  
Timothy B. Harrington ◽  
Stephen H. Schoenholtz
Keyword(s):  
Forest Regeneration ◽  
Timber Harvest ◽  
Douglas Fir ◽  
Soil Productivity ◽  
Short Term ◽  
Vegetation Control ◽  
Competing Vegetation ◽  
Scotch Broom ◽  
Considerable Research ◽  
Survival And Growth

Although considerable research has focused on the influences of logging debris treatments on soil and forest regeneration responses, few studies have identified whether debris effects are mediated by associated changes in competing vegetation abundance. At sites near Matlock, Washington, and Molalla, Oregon, studies were initiated after timber harvest to quantify the effects of three logging debris treatments (dispersed, piled, or removed) on the development of competing vegetation and planted Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii ). Each debris treatment was replicated with initial and annual vegetation control treatments, resulting in high and low vegetation abundances, respectively. This experimental design enabled debris effects on regeneration to be separated into effects mediated by vegetation abundance and those independent of vegetation abundance. Two to three years after treatment, covers of Scotch broom ( Cytisus scoparius (L.) Link) at Matlock and trailing blackberry ( Rubus ursinus Cham. & Schltdl.) at Molalla were over 20% greater where debris was piled than where it was dispersed. Debris effects on vegetation abundance were associated with 30% reductions in the survival of Douglas-fir at Matlock (r2 = 0.62) and the stem diameter at Molalla (r2 = 0.39). Douglas-fir survival and growth did not differ among debris treatments when effects were evaluated independent of vegetation abundance (i.e., with annual vegetation control), suggesting negligible short-term effects of debris manipulation on soil productivity.

scholarly journals Nine-Year Response of Hardwood Understory to Organic Matter Removal and Soil Compaction

2008 ◽  
Vol 25 (1) ◽  
pp. 25-31 ◽  
Author(s):  
Felix Ponder
Keyword(s):  
Organic Matter ◽  
Weed Control ◽  
Soil Compaction ◽  
Understory Vegetation ◽  
Soil Productivity ◽  
Organic Matter Removal ◽  
Woody Vines ◽  
Plant Groups ◽  
Whole Tree ◽  
Measurement Period

Abstract The effects of three levels of organic matter removal (OMR) and three levels of soil compaction (SC) on the development of understory vegetation in a central hardwood forest were evaluated 9 years after treatments were applied as part of a national program of long-term soil productivityresearch. The three levels of biomass removal (OMR) were removal of merchantable boles only (OM0), removal of the whole tree (OM1), and removal of the whole tree plus forest floor (OM2). The three levels of soil compaction (SC) were none (C0), medium (C2), and severe (C2). Weeds were controlledin all plots for the first 2 years. Understory vegetation within 81 7.9-m2 subplots was inventoried by species and quantified into plant groups of woody (trees, shrubs, and woody vines) and herbaceous (annuals, perennials, and grasses) at year 5 (after 3 years of no weed control)and year 9 (after 7 years of no weed control). Vegetation was analyzed for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). OMR did not significantly affect the overall number of plants over the 5-year measurement period, but there were differences for both woodyvines and grasses, which were highest in the OM0 treatment in 1999, but by 2003, they were not different. There were no differences in plant numbers among plant groups for SC in the 1999 measurement period between treatments for any plant group, but there were significantly fewer trees andwoody vines in the C2 treatments than in the C0 or C1 treatments in 2003; the opposite was true for herbaceous annuals, which were highest in C1 and C2 treatments. Over the 5-year measurement period, only the height of woody vines was significantly affected by OMR, but SC significantly affectedthe height of all plant groups over the 5-year measurement period. Annually, however, trees were tallest in the OM0 and C0 treatment than in OM2 and C2 treatments. The annual height of other plants, excluding trees, was affected only 1 year of 5 by OMR. Fewer trees and shorter trees in thesevere compaction treatment suggest that, in the short term, soil productivity has been affected on the site.

Soil organic matter and nutrient pools under long-term non-burning management of sugar cane

2010 ◽  
Vol 61 (3) ◽  
pp. 375-383 ◽  
Author(s):  
L. P. Canellas ◽  
J. G. Busato ◽  
L. B. Dobbss ◽  
M. A. Baldotto ◽  
V. M. Rumjanek ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Sugar Cane ◽  
Nutrient Pools
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