Weight loss of litter and cellulose bags in a thinned white spruce forest in interior Alaska

1978 ◽  
Vol 8 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Harald Piene ◽  
Keith Van Cleve

Thinning in a white spruce, Piceaglanca (Moench) Voss, forest in interior Alaska stimulated organic matter decomposition in the forest floor as indicated by weight loss of litter and cellulose bags. The general higher weight loss in the most heavily thinned plot is attributed to observed higher average seasonal temperatures. Cellulose bags placed in the boundary between the fermentation–humus and the humus–mineral soil layers of the forest floor showed a significantly higher weight loss than those placed on top of the litter layer. This was attributed to more favorable moisture conditions and a more direct contact with the decomposing microbial populations in the fermentation–humus and humus–mineral soil layers.Regardless of thinning treatment, elements were grouped according to their rate of release from decomposing organic matter as follows: K > Mg > C ≈ P ≈ N ≈ Ca, where potassium is lease resistant. Since relatively small differences in weight loss of litter bags were observed between the treatments, similar studies should extend over a longer period in order to obtain a better understanding of the decomposition processes.

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.


1985 ◽  
Vol 15 (1) ◽  
pp. 174-176
Author(s):  
D. C. Eidt ◽  
C. A. A. Weaver

Fenitrothion in oil and water-based formulations at the conventional aerial emission rate and 10 times that rate, and adjuvants alone at 10 times the aerial emission rate, had no effect on the decomposition rate of white spruce foliage, as indicated by weight loss.


1989 ◽  
Vol 19 (12) ◽  
pp. 1648-1650 ◽  
Author(s):  
Elizabeth Anne France ◽  
Dan Binkley ◽  
David Valentine

After 27 years of stand development, the accumulated forest floor under replicated plots of white pine (Pinusstrobus L.), white spruce (Piceaglauca (Moench) Voss), paper birch (Betulapapyrifera Marsh.), and silver maple (Acersaccharinum L.) ranged from 240 g/m2 under maple to 3680 g/m2 under white pine. Forest floor pH ranged from a low under maple of 3.7 to a high under white spruce of 5.9. No significant differences were found in pH in 0–15 cm depth mineral soil; however, substantial differences in the acid neutralization capacities were evident among species, with soils under maple showing the lowest capacity to resist further acidification.


1986 ◽  
Vol 3 (1) ◽  
pp. 16-18 ◽  
Author(s):  
John Zasada ◽  
Rodney Norum

Abstract Broadcast burning following harvesting on flood-plain sites in Alaska substantially decreased residual organic material and increased exposed mineral soil. Two forest types were studied: white spruce/alder/feathermoss and white spruce/alder/lingenberry/feathermoss. The latter site contained permafrost. Fuel was reduced 67% and 81%, respectively; organic horizon thickness was decreased 43% to 2.9 in (7.4 cm) and 55% to 2.5 in (6.4 cm), respectively; and mineral soil exposure was 13% and 8%, respectively. Burning created good conditions for planting on both types. In addition, mechanical site preparation to increase mineral soil exposure appears to be necessary to achieve adequate, well-distributed regeneration from seed. North. J. Appl. For. 3:16-18, Mar. 1986.


1989 ◽  
Vol 19 (11) ◽  
pp. 1389-1396 ◽  
Author(s):  
C. T. Dyrness ◽  
K. Van Cleve ◽  
J. D. Levison

Soil chemical properties were studied after a wildfire in stands of white spruce (Piceaglauca (Moench) Voss), black spruce (Piceamariana (Mill.) B.S.P.), paper birch (Betulapapyrifera Marsh.), and quaking aspen (Populustremuloides Michx.). Samples of the forest floor and surface 5 cm of mineral soil were collected from burned sites and unburned controls and analyzed soon after the fire. With the exception of soil pH, effects of the fire on soil chemistry differed among the four forest types. Generally, amounts of exchangeable K, Ca, and Mg did not appreciably increase in the forest floor and surface mineral soil except in heavily burned areas in white spruce and black spruce. Fire reduced amounts of N by about 50% in white spruce, aspen, and birch forest floors. In black spruce, quantities of N were slightly higher in heavily burned locations. Forest floor C:N ratios were substantially lower in heavily burned locations in white spruce and black spruce than in unburned controls. Burning did not have a marked influence on supplies of available P in the forest floor, except in heavily burned black spruce, where average amounts were 12.50 g/m2 versus only 0.46 g/m2 in the control. Burning caused more moderate gains in available P in surface mineral soils under aspen and white spruce. We concluded that fire caused marked short-term changes in soil chemistry in the four forest types. How long these changes will persist is unknown.


Radiocarbon ◽  
2006 ◽  
Vol 48 (3) ◽  
pp. 337-353 ◽  
Author(s):  
Femke H Tonneijck ◽  
Johannes van der Plicht ◽  
Boris Jansen ◽  
Jacobus M Verstraten ◽  
Henry Hooghiemstra

Volcanic ash soils (Andosols) may offer great opportunities for paleoecological studies, as suggested by their characteristic accumulation of organic matter (OM). However, understanding of the chronostratigraphy of soil organic matter (SOM) is required. Therefore, radiocarbon dating of SOM is necessary, but unfortunately not straightforward. Dating of fractions of SOM obtained by alkali-acid extraction is promising, but which fraction (humic acid or humin) renders the most accurate 14C dates is still subject to debate. To determine which fraction should be used for 14C dating of Andosols and to evaluate if the chronostratigraphy of SOM is suitable for paleoecological research, we measured 14C ages of both fractions and related calibrated ages to soil depth for Andosols in northern Ecuador. We compared the time frames covered by the Andosols with those of peat sequences nearby to provide independent evidence. Humic acid (HA) was significantly older than humin, except for the mineral soil samples just beneath a forest floor (organic horizons), where the opposite was true. In peat sections, 14C ages of HA and humin were equally accurate. In the soils, calibrated ages increased significantly with increasing depth. Age inversions and homogenization were not observed at the applied sampling distances. We conclude that in Andosols lacking a thick organic horizon, dating of HA renders the most accurate results, since humin was contaminated by roots. On the other hand, in mineral soil samples just beneath a forest floor, humin ages were more accurate because HA was then contaminated by younger HA illuviated from the organic horizons. Overall, the chronostratigraphy of SOM in the studied Andosols appears to be suitable for paleoecological research.


1983 ◽  
Vol 13 (5) ◽  
pp. 747-766 ◽  
Author(s):  
Keith Van Cleve ◽  
Lola Oliver ◽  
Robert Schlentner ◽  
Leslie A. Viereck ◽  
C. T. Dyrness

This paper considers the productivity and nutrient cycling in examples of the major forest types in interior Alaska. These ecosystem properties are examined from the standpoint of the control exerted over them by soil temperature and forest-floor chemistry. We conclude that black spruce Piceamariana (Mill.) B.S.P. occupies the coldest, wettest sites which support tree growth in interior Alaska. Average seasonal heat sums (1132 ± 32 degree days (DD)) for all other forest types were significantly higher than those encountered for black spruce (640 ± 40 DD). In addition, black spruce ecosystems display the highest average seasonal forest-floor and mineral-soil moisture contents. Forest-floor chemistry interacts with soil temperature in black spruce to produce the most decay-resistant organic matter. In black spruce the material is characterized by the highest lignin content and widest C/N (44) and C/P (404) ratios. Across the range of forest types examined in this study, soil temperature is strongly related to net annual aboveground tree production and the annual tree requirement for N, P, K, Ca, and Mg. Forest floor C/N and C/P ratios are strongly related to annual tree N and P requirement and the C/N ratio to annual tree production. In all cases these controls act to produce, in black spruce, the smallest accumulation of tree biomass, standing crop of elements, annual production, and element requirement in aboveground tree components.


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.


2005 ◽  
Vol 35 (9) ◽  
pp. 2118-2129 ◽  
Author(s):  
E S Kane ◽  
D W Valentine ◽  
E AG Schuur ◽  
K Dutta

The amount of soil organic carbon (SOC) in stable, slow-turnover pools is likely to change in response to climate warming because processes mediating soil C balance (net primary production and decomposition) vary with environmental conditions. This is important to consider in boreal forests, which constitute one of the world's largest stocks of SOC. We investigated changes in soil C stabilization along four replicate gradients of black spruce productivity and soil temperature in interior Alaska to develop empirical relationships between SOC and stand and physiographic features. Total SOC harbored in mineral soil horizons decreased by 4.4 g C·m–2 for every degree-day increase in heat sum within the organic soil across all sites. Furthermore, the proportion of relatively labile light-fraction (density <1.6 g·cm–3) soil organic matter decreased significantly with increased stand productivity and soil temperature. Mean residence times of SOC (as determined by Δ14C) in dense-fraction (>1.6 g·cm–3) mineral soil ranged from 282 to 672 years. The oldest SOC occurred in the coolest sites, which also harbored the most C and had the lowest rates of stand production. These results suggest that temperature sensitivities of organic matter within discrete soil pools, and not just total soil C stocks, need to be examined to project the effects of changing climate and primary production on soil C balance.


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