Boreal forest ecosystem dynamics. II. Application of the model to four vegetation types in interior Alaska

2000 ◽  
Vol 30 (6) ◽  
pp. 1010-1023 ◽  
Author(s):  
John Yarie

The Spatial Alaskan Forest Ecosystem Dynamics (SAFED) model was validated across four of the most common vegetation types found in interior Alaska. The vegetation types were an alder (Alnus spp.) - balsam poplar (Populus balsamifera L.) site (FP2), an old-growth balsam poplar and white spruce (Picea glauca (Moench) Voss) site (FP3), a mixed deciduous (primarily birch (Betula papyrifera Marsh.) and aspen (Populus tremuloides Michx.)) and white spruce site (UP2), and a mature white spruce site (UP3). The FP site types are common on the floodplain along the Tanana River and the UP site types are common in the uplands in interior Alaska. SAFED is based on nitrogen productivity for vegetation growth, litter fall quantity and quality, and microbial efficiency for forest floor decomposition. The state factors (climate, topography, and disturbance) are used to describe a broad-scale classification of the landscape to define basic limitations for the driving variables. Climate and ecosystem-level disturbances are handled as restricted stochastic processes. The model has been programed in a spatial framework as an ARC/INFO AML within the GRID package. The current version of the model has been validated as functional from an individual tree basis (1-m2 cell size) in a number of forest types found in interior Alaska. The growth, litter fall, and forest floor decomposition were compared with data from the sites. An estimate of yearly carbon balance for the four sites was calculated.

2000 ◽  
Vol 30 (6) ◽  
pp. 998-1009 ◽  
Author(s):  
John Yarie

Modeling the biology of forest ecosystems has been devoted to a combination of theoretical and empirical approaches representing the function of a forest ecosystem generally within an undefined spatial context. Moving to a large spatial context will require the use of theoretical representations of critical ecosystem functions that can be represented on an individual cell basis. A Spatial Alaskan Forest Ecosystem Dynamics (SAFED) model was developed that is based on the nitrogen productivity concept for forest growth, litter fall quality, and microbial efficiency for forest floor decomposition. Climate and ecosystem disturbances were handled as restricted stochastic processes. The restriction was based on known state-factor relationships. The state factors are used to describe a broad-scale classification of the landscape to define basic limitations for the randomly derived driving variables used in the model. The model has been programed as ARC/INFO macro language within the GRID package. The current version of the model has been verified as functional from an individual tree basis (1-m2 cell size) within an old-growth white spruce (Picea glauca (Moench) Voss) forest found in interior Alaska.


2005 ◽  
Vol 35 (8) ◽  
pp. 2045-2055 ◽  
Author(s):  
Richard Kabzems ◽  
Sybille Haeussler

Retaining organic matter and preventing soil compaction are important factors affecting the sustainability of managed forests. To assess how these factors affect short-term ecosystem dynamics, pre-treatment and 1 year and 5 year post-treatment soil properties and post-treatment tree growth responses were examined in a boreal trembling aspen (Populus tremuloides Michx.) dominated ecosystem in northeastern British Columbia, Canada. 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 and white spruce (Picea glauca (Moench) Voss). The compaction treatments had no effect on aspen regeneration density. At year 5, heights of both aspen and white spruce were negatively correlated (r2 > 0.31, p < 0.0001) with upper mineral soil bulk density and were lowest on forest floor removal treatments, where minimal recovery from compaction was observed. There was some evidence for recovery of soil properties to preharvest conditions where expansion of herbaceous vegetation increased soil organic matter.


1993 ◽  
Vol 23 (5) ◽  
pp. 964-969 ◽  
Author(s):  
K.M. Klingensmith ◽  
K. Van Cleve

Cold climatic conditions govern the productivity of taiga forests, yet within a successional sequence the microclimatic and biogeochemical variations also have a major effect on soil microbial activities, thus affecting plant productivity through nutrient availability. Nitrogen mineralization and nitrification were measured in primary-successional floodplain forests of interior Alaska. Forest floor and mineral soils from an early (open willow), middle (poplar–alder), and late (white spruce) successional stage were used. The effects of temperature, moisture, and NH4+ were tested in the laboratory for each of the successional stages. Potential nitrification was estimated using the chlorate-inhibition technique. Surface mineral soils and white spruce forest floor had low to undetectable rates of nitrogen mineralization and nitrification (<1–3 μg N•g−1•d−1). The poplar–alder forest floor had the most pronounced seasonal patterns and the highest rates of net NH4+ mineralization (<1–7 μg N•g−1•d−1) and net nitrification (<1–21 μg N•g−1•d−1). Temperature was limiting in early and midsuccessional stages, and both moisture and temperature were limiting in the later white spruce stage. Ammonium additions increased nitrification only in the poplar–alder forest floor, suggesting the NH4+ is not limiting in the other successional stages. The chlorate inhibition assay indicated that a considerable portion of the nitrification in the poplar–alder forest floor may be due to heterotrophic activity.


2016 ◽  
Vol 1 (3) ◽  
pp. 57
Author(s):  
Tonggo Sinaga

The research was conducted in mountain rain forest of Sibolangit, Deli Serdang, Northen Sumatera. The objectives of this research are to know litter fall productivity, decomposition and litterfall nutrients. Litterfall is the fallen leaves, twigs, flowers and fruits to forest-floor, which one of the input of nutrients to anorganic sril. This input is one of the nutrients cycling to forest ecosystem and the other form atmosfer and a lot of animals. Based on available data on 20 traps, litterfall productivity 5,91 gr/m2/week or 3073,2 kg/ha/year in high topography. Litterfall productivity 4,92gr/m2/week or 2558,4 kg/ha/year in low topography. Litterfall decomposition (lossed of weight) about 25,48% in 30 days ( 1 month ) for meranti ( Shorea sp ) and leaves of Ficus sp had lossed of weight about 8,09% in 30 days ( 1 month ). Ration C/N (Carbon-Nitrogen) litterfall and soil moisture made differrent litterfall decomposition (lossed of weight)   Keywords : Productivity, Decomposition, Litterfall, Productivity.


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.


1993 ◽  
Vol 23 (11) ◽  
pp. 2389-2394 ◽  
Author(s):  
R.D. Blew ◽  
D.R. Iredale ◽  
D. Parkinson

Rates of transfer of nitrogen in throughfall were measured in a Piceaglauca (Moench) Voss forest in southwest Alberta, Canada. Total annual flux of N in throughfall was estimated to be 6.8 kg•ha−1•year−1. The highest rates of N deposition in throughfall occurred during the spring. The pattern of seasonal variation of N in throughfall suggested that different processes of N accumulation in and loss from the canopy may have been operating at different times of the year. Annual leaching of N from the canopy was estimated to be 4.09 kg•ha−1•year−1 and represented 24% of the total amount of N returned to the forest floor (leachates plus litter fall).


1983 ◽  
Vol 13 (5) ◽  
pp. 703-720 ◽  
Author(s):  
Leslie A. Viereck ◽  
C. T. Dyrness ◽  
Keith Van Cleve ◽  
M. Joan Foote

Vegetation, forest productivity, and soils of 23 forest stands in the taiga of interior Alaska are described. The stands are arranged on an environmental gradient from an aspen (Populustremuloides Michx.) stand on a dry, steep south-facing bluff, to open black spruce (Piceamariana (Mill.) B.S.P.) stands underlain by permafrost on north-facing slopes. The coldest site is a mixed white spruce (Piceaglauca (Moench) Voss) and black spruce woodland at the treeline. Mesic upland sites are represented by successional stands of paper birch (Betulapapyrifera Marsh.) and aspen, and highly productive stands of white spruce. Several floodplain stands represent the successional sequence from productive balsam poplar (Populusbalsamifera L.) and white spruce to black spruce stands underlain by permafrost on the older terraces. The environmental gradient is described by using two soil factors: soil moisture and annual accumulated soil degree days (SDD), which range from 2217 SDD for the warmest aspen stand to 480 SDD for the coldest permafrost-dominated black spruce site. Soils vary from Alfie Cryochrepts on most of the mesic sites to Histic Pergelic Cryochrepts on the colder sites underlain by permafrost. A typical soil profile is described for each major forest type. A black spruce stand on permafrost has the lowest tree standing crop (15806 g•m−2) and annual productivity (56 g•m−2•year−1) whereas a mature white spruce stand has the largest tree standing crop (24 577 g•m−2) and an annual productivity of 540 g•m−2•year−1, but the successional balsam poplar stand on flood plain alluvium has the highest annual tree increment (952 g•m−2•year−1). The study supports the hypothesis that black spruce is a nutrient poor, unproductive forest type and that its low productivity is primarily the result of low soil temperature and high soil moisture.


2021 ◽  
Author(s):  
Patrick F. Sullivan ◽  
Annalis H. Brownlee ◽  
Sarah B.Z. Ellison ◽  
Sean M.P. Cahoon

1999 ◽  
Vol 75 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Brian Harvey

The Lake Duparquet Research and Teaching Forest is situated in northwestern Quebec in the Boreal Shield Ecozone. Managed by two constituents of the Université du Québec, in collaboration with two forest companies, Norbord and Tembec, the Lake Duparquet Forest has a strong research program focussed on natural forest ecosystem dynamics that provides the scientific basis for management and silvicultural trials recently begun in the Forest. A bibliographical review of research activities is presented. Keywords: boreal, mixedwood, natural dynamics, fire, disturbance, ecosystem management, silviculture


Sign in / Sign up

Export Citation Format

Share Document