scholarly journals Influence of forest age on forms of carbon in Douglas-fir soils in the Oregon Coast Range

1998 ◽  
Vol 28 (3) ◽  
pp. 390-395 ◽  
Author(s):  
James A Entry ◽  
William H Emmingham

The amount and type of carbon (C) in a forest soil reflects the past balance between C accumulation and loss. In an old-growth forest soil, C is thought to be in dynamic equilibrium between accumulations and losses. Disturbance upsets this equilibrium by altering the microclimate, the amount and type of vegetation growing on a site, and properties that affect organic matter decomposition. We measured total C and forms of soil C in the L, F, and H layers and in the light fraction of soil organic matter in the 0-10 cm of mineral soil in old-, second-, and young-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) soils in the Oregon Coast Range. Total C in L, F, and H layers and in organic material in the top 10 cm of mineral soil in old-growth forests was higher than in young- or second-growth forests. Old-growth forests had a higher lignin concentration and lower concentrations of sugar, hemicellulose, and cellulose in the L, F, and H layers and in the light fraction of organic material than second- or young-growth forests. Old-growth forests had greater amounts of fats, waxes, and oils, sugar, cellulose, and lignin, in the L, F, and H layers per square hectare and greater amounts of hemicellulose, cellulose, and lignin in the light fraction of organic matter in the 0-10 cm of mineral soil per square hectare than young- and second-growth forests. Concentrations of fats, waxes, and oils, sugar, and tannin in the light fraction of organic matter in the 0-10 cm of mineral soil did not differ with forest age.

2011 ◽  
Vol 41 (1) ◽  
pp. 195-210 ◽  
Author(s):  
Alison Cross ◽  
Steven S. Perakis

Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.


1995 ◽  
Vol 25 (1) ◽  
pp. 114-120 ◽  
Author(s):  
James A. Entry ◽  
William H. Emmingham

A substantial fraction of the organic matter and plant essential nutrients in forest ecosystems are contained in the soil. The role of soils in nutrient storage and availability is an essential component of ecosystem function and stability. The top 10 cm of soil contains the highest concentration of nutrients. To determine the influence of forest age on nutrient storage and availability in riparian soils, we compared concentrations, storage, and extractability of plant nutrients in the litter layer and top 10 cm of mineral soil in old-, second-, and young-growth riparian forests. The analysis of variance for nutrient concentration, nutrient storage, or nutrients extracted in both the litter layer and top 10 cm of mineral soil showed no significant differences among sites or seasons for any nutrient; only differences among forest ages will be discussed. Concentrations of N, P, Mg, Mn, and Cu in forest litter did not differ by forest age, but concentrations of K, Ca, and B were significantly higher in old-growth forest litter than in the litter of second-or young-growth forests. In mineral soil, the concentrations of all nutrients were statistically equal for all forest ages. Old-growth forests stored significantly (P ≤ 0.05) greater amounts of all nutrients measured in the litter layer, and greater amounts of N, P, and K in the mineral soil, than were stored in second- or young-growth forests. Greater amounts of P, B, and Zn were extracted from old-growth forest litter than from either second- or young-growth forest litter, and greater amounts of P, K, Mn, B, and Zn were extracted from old-growth mineral soil than from second- or young-growth mineral soil. The amount of each nutrient stored in the litter layer of the different-aged forests correlated curvilinearly with the amount of C in the litter layer of these forests; r2 ranged from 0.60 to 0.83. Also, the amount of N, K, and Ca stored in the mineral soil correlated curvilinearly with the amount of C in the soil; r2 ranged from 0.50 to 0.76.


1979 ◽  
Vol 9 (2) ◽  
pp. 245-256 ◽  
Author(s):  
Robert Fogel ◽  
Gary Hunt

The allocation of biomass and the turnover time of various components were measured from August 1976 to August 1977 in a young, second-growth Douglas-fir stand in the Oregon Coast Range. Allocation of biomass among the tree components was 14 732 kg foliage ha−1, 30 455 kg branches ha−1, 212 941 kg boles ha−1, 49 289 kg nonmycorrhizal roots ha−1, and 15 015 kg host portion of mycorrhizae ha−1. Biomass allocation of fungal components was 10 009 kg mycorrhizal mantles ha−1, 2785 kg Cenococcumgeophilum sclerotia ha−1, 65 kg sporocarps ha−1, 369 kg litter hyphae ha−1, and 6666 kg soil hyphae ha−1. The forest floor was composed of 6970 kg fine (<2 mm) litter ha−1, 6564 kg coarse (2–25 mm) litter ha−1, and 5500 kg log (>25 mm) litter ha−1. Soil organic matter (<0.494 mm) was 87 600 kg ha−1. Total annual stand throughput was 30 324 kg ha−1, excluding soil organic matter throughput. Of this total, 50.5% was accounted for by fungal throughput, 39.5% by tree throughput, and 10.0% by forest floor throughput.


2005 ◽  
Vol 35 (6) ◽  
pp. 1411-1421 ◽  
Author(s):  
Arthur L Fredeen ◽  
Claudette H Bois ◽  
Darren T Janzen ◽  
Paul T Sanborn

Carbon (C) stocks were assessed for hybrid interior spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.)-dominated upland forests within the Aleza Lake Research Forest in central British Columbia, Canada. Four old-growth (141–250 years old) and four young second-growth (<20 years old) forest plots were established on the two dominant soil texture types, coarse and fine, for a total of 16 plots. Mean total C stocks for old-growth stands ranged from 423 Mg C·ha–1 (coarse) to 324 Mg C·ha–1 (fine), intermediate between Pacific Northwest temperate forests and upland boreal forests. Total C was lower in second-growth stands because of lower tree (mostly large tree stem), forest floor, and woody debris C stocks. In contrast, old-growth forest-floor C stocks ranged from 78 Mg C·ha–1 (coarse) to 35 Mg C·ha–1 (fine), 2.9- and 1.2-fold higher than in corresponding second-growth stands, respectively. Woody debris C stocks in old-growth stands totaled 35 Mg C·ha–1 (coarse) and 31 Mg C·ha–1 (fine), 2.7- and 3.4-fold higher than in second-growth stands, respectively. Mineral soil C to 1.07 m depth was similar across soil type and age-class, with totals ranging from 115 to 106 Mg C·ha–1. Harvesting of old-growth forests in sub-boreal British Columbia lowers total C stocks by 54%–41%.


2001 ◽  
Vol 31 (12) ◽  
pp. 2225-2236 ◽  
Author(s):  
Peter S Homann ◽  
Bruce A Caldwell ◽  
H N Chappell ◽  
Phillip Sollins ◽  
Chris W Swanston

Chemical and microbial soil properties were assessed in paired unfertilized and urea fertilized (>89 g N·m–2) plots in 13 second-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands distributed throughout western Washington and Oregon. A decade following the termination of fertilization, fertilized plots averaged 28% higher total N in the O layer than unfertilized plots, 24% higher total N in surface (0–5 cm) mineral soil, and up to four times the amount of extractable ammonium and nitrate. Decreased pH (0.2 pH units) caused by fertilization may have been due to nitrification or enhanced cation uptake. In some soil layers, fertilization decreased cellulase activity and soil respiration but increased wood decomposition. There was no effect of fertilization on concentrations of light and heavy fractions, labile carbohydrates, and phosphatase and xylanase activities. No increase in soil organic C was detected, although variability precluded observing an increase of less than ~15%. Lack of a regionwide fertilization influence on soil organic C contrasts with several site-specific forest and agricultural studies that have shown C increases resulting from fertilization. Overall, the results indicate a substantial residual influence on soil N a decade after urea fertilization but much more limited influence on soil C processes and pools.


1989 ◽  
Vol 19 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Stephen C. Hart ◽  
Mary K. Firestone

Three indices of nitrogen (N) availability were compared in the field over a 1-year period in an old-growth and a young-growth mixed-conifer forest. The indices utilized were ion exchange resin (IER) bags, buried bags, and a core-IER method employing intact soil cores enclosed in tubes capped at both ends by IER bags. The results from all three methods indicated that in the surface mineral soil, N availability was higher in the young-growth stand than in the old-growth stand. However, seasonal patterns of N availability were generally not well correlated among the methods (correlation coefficients ranged from 0.32 to 0.62). For a given amount of net N mineralized in buried bags, more N accumulated on IER bags placed in the young-growth stand than in those placed in the old-growth stand. This was the result of greater net nitrification in the young-growth stand coupled with the greater mobility of [Formula: see text] relative to [Formula: see text] in soil. Ten-month estimates of net N mineralization measured by the core-IER and buried-bag methods were similar in the young-growth stand (about 42 mg•kg soil−1), but the core-IER estimate was almost twice that of the buried-bag estimate in the old-growth stand (31.7 and 16.8 mg•kg soil−1, respectively). The different sensitivities of the core-IER and buried-bag methods to changes in soil moisture and leaching probably account for much of the difference in their N availability estimates. Results from the core-IER method did reflect the effects of leaching; however, soil water content within the core did not follow changes in soil water content effectively. Because of the greater labor involved in using the core-IER method, its use may be most efficacious in high-precipitation environments, or when in-field soil incubations must be conducted for extended periods of time.


2006 ◽  
Vol 3 (4) ◽  
pp. 479-487 ◽  
Author(s):  
M. R. Hoosbeek ◽  
J. M. Vos ◽  
E. J. Bakker ◽  
G. E. Scarascia-Mugnozza

Abstract. Free air CO2 enrichment (FACE) experiments in aggrading forests and plantations have demonstrated significant increases in net primary production (NPP) and C storage in forest vegetation. The extra C uptake may also be stored in forest floor litter and in forest soil. After five years of FACE treatment at the EuroFACE short rotation poplar plantation, the increase of total soil C% was larger under elevated than under ambient CO2. However, the fate of this additional C allocated belowground remains unclear. The stability of soil organic matter is controlled by the chemical structure of the organic matter and the formation of micro-aggregates (within macro-aggregates) in which organic matter is stabilized and protected. FACE and N-fertilization treatment did not affect the micro- and macro-aggregate weight, C or N fractions obtained by wet sieving. However, Populus euramericana increased the small macro-aggregate and free micro-aggregate weight and C fractions. The obtained macro-aggregates were broken up in order to isolate recently formed micro-aggregates within macro-aggregates (iM-micro-aggregates). FACE increased the iM-micro-aggregate weight and C fractions, although not significantly. This study reveals that FACE did not affect the formation of aggregates. We did, however, observe a trend of increased stabilization and protection of soil C in micro-aggregates formed within macro-aggregates under FACE. Moreover, the largest effect on aggregate formation was due to differences in species, i.e. poplar genotype. P. euramericana increased the formation of free micro-aggregates which means that more newly incorporated soil C was stabilized and protected. The choice of species in a plantation, or the effect of global change on species diversity, may therefore affect the stabilization and protection of C in soils.


2004 ◽  
Vol 82 (6) ◽  
pp. 830-849 ◽  
Author(s):  
Mireille Desponts ◽  
Geneviève Brunet ◽  
Louis Bélanger ◽  
Mathieu Bouchard

The objective of this project was to assess the importance of pristine forests in maintaining the botanical biodiversity of the humid boreal balsam fir forest of eastern Canada. The study was based on a comparative analysis of silviculturally mature second-growth stands and pristine forest stands at two stages of development (senescent and old growth) in the Gaspé Peninsula. The structure and composition of the stands was described, and the abundance of structural attributes evaluated. The communities of nonvascular plant species (mosses, liverworts), lichens, and saprophytic fungi were compared. The study demonstrated that the pristine forest landscape studied was composed largely of old-growth and senescent stands. Old-growth forests are differentiated by their irregular structure. The results regarding nonvascular plant species, lichens, and saprophytic fungi show higher species diversity in old-growth forests, corresponding to higher habitat diversity. Species assemblages were comparable between the pristine forests, but different from those of second-growth stands. Rare species are found more frequently in the old-growth forests. The results indicate that the old-growth balsam fir stands of the Gaspé Peninsula constitute critical habitats for maintaining a large number of species threatened by the gradual disappearance of primeval stands.Key words: forest management, biodiversity, old-growth forest, humid boreal fir forest, nonvascular plants.


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