Decay and nitrogen dynamics of litter from disjunct, congeneric tree species in old-growth stands in northeastern China and Wisconsin

1993 ◽  
Vol 71 (5) ◽  
pp. 693-699 ◽  
Author(s):  
Xiaoyuan Geng ◽  
John Pastor ◽  
Bradley Dewey

Decay and nitrogen dynamics of leaf litter from four tree species in an old-growth forest in northeastern China was measured in a litter-bag experiment and compared with decomposition of congeneric species in a Wisconsin old-growth forest with similar climatic regimes and soil. Leaf litter decay in both China and Wisconsin decreased in the order Acer > Populus > Quercus > Pinus and was negatively correlated with initial lignin content (r = 0.961, P < 0.001). Decay was also correlated with other chemical properties depending on locale. In contrast with decay rates, N-immobilization kinetics were not correlated with litter chemistry or comparable between congeners. Principal component analysis showed that almost half the total variation in litter decay is explained by grouping congeneric species according to litter quality. In northern mixed hardwood–conifer forests, generic similarity implies functional similarity in decomposition and nutrient cycling. Key words: decomposition, China, litter, nitrogen, Wisconsin.

2021 ◽  
Author(s):  
Leszek Bartkowicz ◽  

The aim of the study was to compare a patch-mosaic pattern in the old-growth forest stands developed in various climate and soil conditions occurring in different regions of Poland. Based on the assumption, that the patch-mosaic pattern in the forest reflect the dynamic processes taking place in it, and that each type of forest ecosystem is characterized by a specific regime of natural disturbances, the following hypotheses were formulated: (i) the patches with a complex structure in stands composed of latesuccessional, shade-tolerant tree species are more common than those composed of early-successional, light-demanding ones, (ii) the patch-mosaic pattern is more heterogeneous in optimal forest site conditions than in extreme ones, (iii) in similar site conditions differentiation of the stand structure in distinguished patches is determined by the successional status of the tree species forming a given patch, (iv) the successional trends leading to changes of species composition foster diversification of the patch structure, (v) differentiation of the stand structure is negatively related to their local basal area, especially in patches with a high level of its accumulation. Among the best-preserved old-growth forest remaining under strict protection in the Polish national parks, nineteen research plots of around 10 ha each were selected. In each plot, a grid (50 × 50 m) of circular sample subplots (with radius 12,62 m) was established. In the sample subplots, species and diameter at breast height of living trees (dbh ≥ 7 cm) were determined. Subsequently, for each sample subplot, several numerical indices were calculated: local basal area (G), dbh structure differentiation index (STR), climax index (CL) and successional index (MS). Statistical tests of Kruskal- Wallis, Levene and Generalized Additive Models (GAM) were used to verify the hypotheses. All examined forests were characterized by a large diversity of stand structure. A particularly high frequency of highly differentiated patches (STR > 0,6) was recorded in the alder swamp forest. The patch mosaic in the examined plots was different – apart from the stands with a strongly pronounced mosaic character (especially subalpine spruce forests), there were also stands with high spatial homogeneity (mainly fir forests). The stand structure in the distinguished patches was generally poorly related to the other studied features. Consequently, all hypotheses were rejected. These results indicate a very complex, mixed pattern of forest natural dynamics regardless of site conditions. In beech forests and lowland multi-species deciduous forests, small-scale disturbances of the gap dynamics type dominate, which are overlapped with less frequent medium-scale disturbances. In more difficult site conditions, large-scale catastrophic disturbances, which occasionally appear in communities formed under the influence of gap dynamics (mainly spruce forests) or cohort dynamics (mainly pine forests), gain importance.


Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 4 ◽  
Author(s):  
Srđan Keren ◽  
Miroslav Svoboda ◽  
Pavel Janda ◽  
Thomas A. Nagel

Structural indices are often proposed as guiding measures for increasing structural heterogeneity. However, few studies have examined the association between such indices and conventional stand attributes. The primary objectives of this study were to evaluate changes in structural heterogeneity and tree species diversity at different plot sizes and to quantify the relationships between conventional stand attributes (mean tree diameter, absolute tree density, basal area, species proportion) and structural indices in a mixed old-growth forest in Southeast Europe. Paired tests were used to identify significant changes in structural heterogeneity with increased plot area, while the relationships between stand attributes and analyzed indices (Gini, diameter differentiation, species mingling, and Shannon’s index) were evaluated with Pearson’s correlations. The index values of Gini, diameter differentiation, and tree species mingling were rather stable with the increase of plot size, whereas tree species diversity increased significantly with the increase of plot area from 200 m2 to 1500 m2. The measures of tree species mingling and tree species diversity were strongly associated with each other, while their association with diameter variability was weak to moderately strong. Tree species mingling index was strongly associated with the changes in tree species proportions. However, conventional stand attributes were generally not strongly correlated with the examined indices. For restoring and maintaining old-growth characteristics, forest managers may use structural indices to increase small-scale structural heterogeneity, tree species mingling, and diversity, but only as an additional set of measures, not as surrogates for conventional stand attributes.


Forests ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 957 ◽  
Author(s):  
Liu ◽  
Zhu ◽  
Wang ◽  
Ma ◽  
Meng

Subtropical natural forests are unique due to their ecological and economic functions. However, most of these forests are highly degraded, which impairs the ability to provide ecological and economic benefits. Enrichment planting is an important approach to restore natural degraded forests. Species arrangement is of great importance to inform enrichment planting. Species association refers to the interrelationship of different species occupying a habitat and is a static description of the organic connection formed by the interaction of species. Species association, therefore, provides a scientific basis for species arrangement in enrichment planting. Additionally, because an old-growth forest is a climax community that has attained great age without significant disturbance, the species association in an old-growth forest can provide valuable information on the reference conditions for forest management. In this study, the species association between dominant tree species (including saplings and adult trees) was investigated in an old-growth forest in the Gutianshan National Nature Reserve in Zhejiang province in subtropical China. The objective of the study was to inform species arrangement for enrichment planting. The result showed that the overall species association exhibited a significant net positive association, indicating a dynamic balance of stable structure and species composition in the old-growth forest. Additionally, the pairwise species association was examined using the χ2 test, the Dice index, and Spearman’s rank correlation coefficient; significant positive and negative pairwise species associations were detected. Based on the species association and the light requirements of the tree species, an optimal species arrangement was determined to support enrichment planting for restoring natural degraded forests. It is expected that the results of this study will contribute to the restoration of natural degraded forests in subtropical China.


1996 ◽  
Vol 28 (5) ◽  
pp. 443-463 ◽  
Author(s):  
Mikko Kuusinen

AbstractEpiphytic lichen and bryophyte species composition, richness and diversity were surveyed on basal trunks of six common old-growth forest tree species, Picea abies, Pinus sylvestris, Betula pendula, Alnus incana, Salix caprea and Populus tremula, in two old-growth forest areas, one in southern and one in middle boreal Finland. The average species numbers per tree ranged from 18 (Picea) to 27 (Salix) in the southern and from 20 (Populus) to 31 (Salix) in the middle boreal area. A few widespread habitat-generalist species, such as the foliose lichens Hypogymnia physodes and Platismatia glauca, were most abundant on all the tree species, except Populus. Most other epiphyte species showed at least a slight preference for one or two tree species. Populus proved to have the most distinct flora characterized by the abundance of certain, rather specialized crustose lichens and bryophytes. The number of species that occurred on only one tree species was highest on Populus (9) in the southern and on Alnus (18) in the middle boreal area. Differences in bark acidity and structure were the most likely explanations for the differences between tree species in the epiphytic flora and diversity. Salix and Populus were the most important of the tree species studied for the conservation of epiphyte diversity in the boreal forests of Finland.


2019 ◽  
Vol 5 (3) ◽  
pp. eaau3114 ◽  
Author(s):  
Danaë M. A. Rozendaal ◽  
Frans Bongers ◽  
T. Mitchell Aide ◽  
Esteban Alvarez-Dávila ◽  
Nataly Ascarrunz ◽  
...  

Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes.


1992 ◽  
Vol 22 (3) ◽  
pp. 306-314 ◽  
Author(s):  
Stephen C. Hart ◽  
Mary K. Firestone ◽  
Eldor A. Paul

A litter-bag technique was used to measure decay rates and assess changes in organic and inorganic constituents of ponderosa pine (Pinusponderosa Laws.) needle litter during decomposition over a 2-year period in old- and young-growth forests in the Sierra Nevada of California. Rates of mass loss were among the lowest reported for temperate and boreal forests, with annual decomposition constants of about 0.08 and 0.18 year−1 for the old- and young-growth forests, respectively. Apparently, the temporal separation of warm temperatures and moist conditions found in Mediterranean-type climates severely limits decomposition in these coniferous forests. In the old-growth forest, comparison of estimates of tree nutrient uptake with net releases of nutrients from fine litter during their 1st year of decomposition suggests that recent litter fall potentially acts as a significant source of P, Mg, and K for tree uptake in this forest; in contrast, recently fallen litter acts as a net sink for N, S, and Ca. Despite initially lower indices of litter quality for litter originating from the old–growth relative to the young–growth forest, no significant difference in decomposition rates of these two litter age-classes was found when placed at either site. This result does not support the hypothesis that decreases in decomposition rates during forest development are driven by decreases in the quality of litter fall.


2000 ◽  
Vol 78 (10) ◽  
pp. 1309-1318 ◽  
Author(s):  
Angélica Camacho-Cruz ◽  
Mario González-Espinosa ◽  
Jan H.D Wolf ◽  
Bernardus HJ De Jong

Germination and seedling survival of native tree species were studied in nursery (June-November 1998) and forest stands with varying dominance by pines in the central highlands of Chiapas (Mexico; June 1998 - November 1999). Species used are regarded as typical of mid- and late-successional habitats: Cornus disciflora Sessé & Mociño ex DC., Cornus excelsa H.B.K., Drimys granadensis L.f. var. mexicana (DC.) A.C. Smith, Liquidambar styraciflua L., Persea americana L., Quercus laurina H. & B., and Ternstroemia lineata (DC.) ssp. chalicophyla (Loesener) Bartholomew. Nursery treatments included presence and composition of litter collected from replicated plots of three forest types: old-growth forest, mixed pine-oak forest, and pine-dominated forest. Germination and seedling emergence of P. americana in the nursery were complete for all factor combinations. Cornus disciflora and L. styraciflua showed highest germination (p < 0.05) when sown in soil from old-growth forest and covered with litter of oak-broad-leaved species. In the field, differences (p < 0.05) among forest types (degree of pine dominance) were observed for C. disciflora (lowest germination in pinelands, 17%), D. granadensis (highest survival in old-growth forest, 23%), and Q. laurina (higher survival in pinelands, 54%). Natural recruitment and survival of seedlings were higher in old-growth forests. We conclude that oak litter may favor germination and early establishment of the studied species. However, the reintroduction of some of the studied species (C. excelsa, Q. laurina, and T. lineata) may be attempted with direct sowing on the forest floor of severely disturbed and species-poor pinelands.Key words: Cornus, Liquidambar, litter, Persea, Pinus, Quercus, seedling establishment, seeds.


1976 ◽  
Vol 54 (5-6) ◽  
pp. 419-436 ◽  
Author(s):  
J. D. Lousier ◽  
D. Parkinson

Amounts of autumn tree leaf litter fall, understory litter input, tree leaf litter nutrient input, and rates of dry weight loss in decomposing leaf litter were estimated in an aspen woodland (Populus tremuloides Michx. – P. balsamifera L.) site in the Rocky Mountains in southwestern Alberta. Tree leaf litter input amounted to 250 g m−2 and comprised 3.7% of the total organic matter in the ecosystem (1.92 × 105 kg ha−1). The ratio of the weight of aspen leaf fall to balsam leaf fall was about 6:1. The tree leaf litter input and the total litter input figures were similar to those for other Northern Hemisphere aspen forests. The understory litter input in the study plots was measured as 99 g m−2. The importance by weight of some of the nutrients returned to the soil via tree leaf litter fall was Ca > N > K > Mg > P > Zn > Fe > Mn > Na > Cu. The total weight of these nutrients returned to the soil was 116 kg ha−1, with N, Ca, and K comprising 89% and Mg and P comprising 9.8% of the total.The dry weight loss of decomposing aspen and balsam leaves was measured at 1-, 5-, 8-, 12-, 18-, 24-, and 30-month intervals by using 3-mm-mesh litter bags, and at 12-, 24-, 36-, 48-, and 60-month intervals by using 10-mm-mesh bags. Litter-bag mesh size was of little consequence to the rate of dry weight loss for the first 12 months, but subsequent dry weight loss was greater in the 3-mm-mesh bags, which maintained higher, more representative, moisture conditions than did the 10-mm-mesh bags. However, tethered leaves lost 1.7 times more weight over the first 12 months of decomposition than did confined litter. The decay rate decline with time and with the depth of the litter bag in the litter layers, with maximum dry weight loss occurring over the period encompassing the fall freeze, winter, and the spring thaw and runoff. Leaf litter placed on north-facing slopes was characterized by significantly slower decay rates than that on south-facing slopes.The dry weight loss for aspen leaf litter was 26.2 ± 2.0% after 12 months. 40.0 ± 1.6% after 30 months, and 58.7% after 60 months (by regression): for balsam litter it was 21.2 ± 1.9% after 12 months, 37.4 ± 1.7% after 30 months, and 47.9% after 60 months (by regression). The highly leachable component of leaf litter was estimated at 23.1% for aspen and 21.4% for balsam. The time required for 99% decomposition was calculated as about 24 years for aspen and about 27 years for balsam, which gives average annual decay rates of 3.2% for aspen and 2.9% for balsam. The decay rate for Populus leaf litter was lower than that for aspen in Alaska and appeared to fit the range for deciduous leaf litter from some forested IBP Tundra Biome sites.


2019 ◽  
Author(s):  
Christopher W. Fernandez ◽  
Craig R. See ◽  
Peter G. Kennedy

AbstractInteractions between symbiotic ectomycorrhizal (EM) and free-living saprotrophs can result in significant deceleration of leaf litter decomposition. While this phenomenon is widely cited, its generality remains unclear, as both the direction and magnitude of EM fungal effects on leaf litter decomposition have been shown to vary among studies. Here we explicitly examine how contrasting leaf litter types and EM fungal communities may lead to differential effects on C and N cycling. Specifically, we measured the response of soil nutrient cycling, litter decay rates, litter chemistry and fungal community structure to the reduction of EM fungi (via trenching) with a reciprocal litter transplant experiment in adjacent Pinus- or Quercus-dominated sites. We found clear evidence of EM fungal suppression of C and N cycling in the Pinus-dominated site, but no suppression in the Quercus-dominated site. Additionally, in the Pinus-dominated site, only the Pinus litter decay rates were decelerated by EM fungi and were associated with decoupling of litter C and N cycling. Our results support the hypothesis that EM fungi can decelerate C cycling via N competition, but strongly suggest that the ‘Gadgil effect’ is dependent on both substrate quality and EM fungal community composition. We argue that understanding tree host traits as well as EM fungal functional diversity is critical to a more mechanistic understanding of how EM fungi mediate forest soil biogeochemical cycling.


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