An analysis of litter nitrogen dynamics using artificial soils across a gradient of forest soil disturbances

2004 ◽  
Vol 84 (2) ◽  
pp. 159-167 ◽  
Author(s):  
J. M. Kranabetter ◽  
B. K. Chapman

The release of nutrients from a standard litter is often assumed to be solely a function of its decomposition rate. We tested whether nitrogen release would also be influenced by soil attributes affected by disturbance, such as interactions with soil microflora. Changes in nitrogen contents of decaying litter (Populus balsamifera) were compared across soil compaction and organic matter removal treatments in central British Columbia, using artificial materials to isolate litter bags from contact with forest floors or mineral soil. After 30 mo, nitrogen content of litter was only slightly higher on artificial soils than actual soils, suggesting that most nitrogen had been lost by leaching. A significant interaction, however, was detected in leaf nitrogen content between organic matter removal and soil compaction treatments that was not found on the artificial soils. This difference in nitrogen release led to a range in C:N ratios of 28 to 32 (from an initial C:N ratio of 52) for leaves at 1.5 g (70% mass loss). The differences in nitrogen release were relatively small and will perhaps be less important than other effects of soil disturbance (such as changes in litter quality) on nitrogen cycling. Key words: Nitrogen, decomposition, litter bag, translocation, compaction, forest floors

2012 ◽  
Vol 88 (03) ◽  
pp. 306-316 ◽  
Author(s):  
Richard Kabzems

Declines in forest productivity have been linked to losses of organic matter and soil porosity. To assess how removal of organic matter and soil compaction affect short-term ecosystem dynamics, pre-treatment and year 1, 5 and 10 post-treatment soil properties and post-treatment plant community responses were examined in a boreal trembling aspen (Populus tremuloidesMichx.)-dominated ecosystem in northeastern British Columbia. The experiment used a completely randomized design with three levels of organic matter removal (tree stems only; stems and slash; stems, slash and forest floor) and three levels of soil compaction (none, intermediate [2-cm impression], heavy [5-cm impression]). Removal of the forest floor initially stimulated aspen regeneration and significantly reduced height growth of aspen (198 cm compared to 472–480 cm) as well as white spruce (Picea glauca [Moench] Voss) height (82 cm compared to 154–156 cm). The compaction treatments had no effect on aspen regeneration density. At Year 10, heights of both aspen and white spruce were negatively correlated with upper mineral soil bulk density and were lowest on forest floor + whole tree removal treatments. Recovery of soil properties was occurring in the 0 cm to 2 cm layer of mineral soil. Bulk density values for the 0 cm to 10 cm depth remained above 86% of the maximum bulk density for the site, a soil condition where reduced tree growth can be expected.


1984 ◽  
Vol 14 (6) ◽  
pp. 763-767 ◽  
Author(s):  
C. Anthony Federer

Organic content of the forest floor decreases for several years after clear-cutting, and then slowly recovers. Thickness, bulk density, organic matter, and nitrogen content of forest floors were measured for 13 northern hardwood stands in the White Mountains of New Hampshire. Stands ranged from 1 to about 100 years in age. Forest-floor thickness varied significantly with stand age, but bulk density, organic fraction, and nitrogen fraction were independent of age. Total organic content of the forest floor agreed very well with data from Covington's (W. W. Covington 1981. Ecology, 62: 41–48) study of the same area. Both studies indicated that mature forest floors have about 80 Mg organic matter•ha−1 and 1.9 Mg nitrogen•ha−1. Within 10 or 15 years after cutting, the organic matter content of the floor decreases to 50 Mg•ha−1, and its nitrogen content to 1.1 Mg•ha−1. The question whether the decrease is rapid and the minimum broad and flat, or if the decrease is gradual and the minimum sharp, cannot be answered. The subsequent increase to levels reached in mature forest requires about 50 years. Some of the initial decrease in organic matter and nitrogen content of the forest floor may be caused by organic decomposition and nitrogen leaching, but mechanical and chemical mixing of floor into mineral soil, during and after the harvest operation, may also be important. The difference is vital with respect to maintenance of long-term productivity.


2004 ◽  
Vol 34 (5) ◽  
pp. 1136-1149 ◽  
Author(s):  
Jeffrey P Battigelli ◽  
John R Spence ◽  
David W Langor ◽  
Shannon M Berch

This study examines the short-term impact of forest soil compaction and organic matter removal on soil mesofauna, in general, and oribatid mite species, in particular. Both soil compaction and organic matter removal reduced the density of soil mesofauna. Stem-only harvesting reduced total mesofauna densities by 20% relative to uncut forest values. A combination of whole-tree harvest and forest floor removal with heavy soil compaction significantly reduced total soil mesofauna densities by 93% relative to the uncut forest control. Removal of the forest floor represents a substantial loss of habitat for most soil mesofauna. The forest floor apparently buffered the mineral soil by limiting both the impact of soil compaction and fluctuations in soil temperature and moisture. The relative abundance of Prostigmata and Mesostigmata increased with treatment severity, whereas that of Oribatida decreased. Species richness of the oribatid mite fauna was reduced as the severity of treatments increased. The number of rare oribatid species (those representing <1% of the total oribatid mite sample) decreased by 40% or more relative to the uncut forest control. Evenness also decreased as treatment severity increased. Oppiella nova and Suctobelbella sp. near acutidens were the dominant oribatid species in both the forest floor and mineral soil, regardless of treatment. Soil compaction and organic matter removal significantly impacted the density and diversity of soil mesofauna and oribatid mite fauna in the short term at these study sites.


2015 ◽  
Vol 45 (8) ◽  
pp. 1045-1055 ◽  
Author(s):  
Anya M. Reid ◽  
William K. Chapman ◽  
John Marty Kranabetter ◽  
Cindy E. Prescott

Soil disturbance from organic matter loss and soil compaction can impair site productivity, but less is known about whether these disturbances also affect forest health (defined here as the presence and severity of damaging pests and diseases, mortality, and overall vigour). We used six long-term soil productivity (LTSP) sites in the interior of British Columbia, Canada to test the effects of organic-matter removal and soil compaction on forest health, and to explore the relationship between forest health response and potential indicators of site sensitivity: mineral soil pH, base saturation, carbon to nitrogen ratio (C:N), carbon to phosphorus ratio (C:P), and calcium to aluminum ratio (Ca:Al). Visual forest health surveys were conducted on 5400 15 and 20 year old lodgepole pine (Pinus contorta Dougl. ex Loud.) trees. Soil disturbance treatments significantly affected forest health metrics, but this response typically differed among sites. Principle component analyses indicated the response of healthy trees was negatively related to soil base saturation, the response of dead or dying trees related to soil C:P, and the response of tree disease related to soil Ca:Al, pH, base saturation, and C:N. We found forest health response to soil disturbance varied among sites with relationships between response and soil chemical properties, suggesting a greater vulnerability of pine stands to disease with increasing soil acidity.


1998 ◽  
Vol 78 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Douglas M. Stone ◽  
John D. Elioff

Forest management activities that decrease soil porosity and remove organic matter have been associated with declines in site productivity. In the northern Lake States region, research is in progress in the aspen (Populus tremuloides Michx. and P. grandidentata Michx.) forest type to determine effects of soil compaction and organic matter removal on soil properties and growth of aspen suckers, associated woody species, herbaceous vegetation, and on stand development. Four treatments: (1) total tree harvest (TTH); (2) TTH plus soil compaction (CPT); (3) TTH plus forest floor removal (FFR); and (4) TTH plus CPT + FFR were applied after winter-harvest of a 70-yr-old aspen stand growing on a loamy sand with a site index(age50) of 20.7 m. The CPT treatment significantly increased bulk density and soil strength of the surface 30 cm of soil and neither have recovered during the 5 yr since treatment. The CPT plots had 19.6 thousand (k) suckers ha−1, less than half that of the TTH and FFR treatments; mean diameter (19.4 mm) and height (271 cm) were greatest on the TTH plots. The disturbance treatments (CPT, FFR, and CPT + FFR) each reduced biomass of foliage, stems, and total suckers compared with the TTH treatment. Total aboveground biomass (herbs + shrubs + suckers) was less than half that of TTH plots. There were 5.0 k saplings (suckers >2.5 cm DBH) ha−1 on the TTH plots, but fewer than 1.0 k ha−1 in the other treatments. The disturbance treatments decreased 5-yr growth of potential crop trees, delayed early stand development, and temporarily reduced stockability and site productivity of an aspen ecosystem. Key words: Soil compaction, organic matter removal, site productivity, stand development


Pedobiologia ◽  
2004 ◽  
Vol 48 (2) ◽  
pp. 121-128 ◽  
Author(s):  
Robert J Eaton ◽  
Mary Barbercheck ◽  
Marilyn Buford ◽  
William Smith

2005 ◽  
Vol 35 (8) ◽  
pp. 2030-2044 ◽  
Author(s):  
Sybille Haeussler ◽  
Richard Kabzems

Organic matter removal and reduced soil aeration porosity during logging are important factors influencing the sustained productivity of managed forest ecosystems. We studied the 4-year effect of these factors on diversity and composition of a trembling aspen (Populus tremuloides Michx.) plant community in northeastern British Columbia, Canada, in a completely randomized experiment with three levels of organic matter removal (tree stems; stems and slash; stems, slash, and forest floor) and three levels of soil compaction (none; intermediate (2-cm impression); heavy (5-cm impression)). Tree stem removal caused the greatest change in species diversity (30% of variance; ANOVA p ≤ 0.01), increasing the dominance of aspen and Calamagrostis canadensis (Michx.) Beauv. over other species. Slash removal had little effect. Forest floor removal caused the greatest compositional change (37% of variance; MANOVA p = 0.001), favoring ruderal over bud-banking species. Presence or absence of forest floor better explained these changes than any soil physical or chemical parameter. Although dominance of aspen over Calamagrostis was positively correlated with soil aeration porosity (R2 = 0.50, n = 27, p < 0.001), there were few differences between intermediate and heavy compaction. In this ecosystem, disturbances that reduce forest floor thickness without compacting soils will likely optimize plant species diversity and enhance aspen regrowth.


Sign in / Sign up

Export Citation Format

Share Document