scholarly journals The Influences of Canopy Species and Topographic Variables on Understory Species Diversity and Composition in Coniferous Forests

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hong Huo ◽  
Qi Feng ◽  
Yong-hong Su
Keyword(s):  
Species Composition ◽  
Variation Partitioning ◽  
Explanatory Power ◽  
Coniferous Forest ◽  
Coniferous Forests ◽  
Spruce Forest ◽  
Understory Species ◽  
Sabina Przewalskii ◽  
Understory Species Composition ◽  
Understory Plant

Understanding the factors that influence the distribution of understory vegetation is important for biological conservation and forest management. We compared understory species composition by multi-response permutation procedure and indicator species analysis between plots dominated by Qinghai spruce (Picea crassifoliaKom.) and Qilian juniper (Sabina przewalskiiKom.) in coniferous forests of the Qilian Mountains, northwestern China. Understory species composition differed markedly between the forest types. Many heliophilous species were significantly associated with juniper forest, while only one species was indicative of spruce forest. Using constrained ordination and the variation partitioning model, we quantitatively assessed the relative effects of two sets of explanatory variables on understory species composition. The results showed that topographic variables had higher explanatory power than did site conditions for understory plant distributions. However, a large amount of the variation in understory species composition remained unexplained. Forward selection revealed that understory species distributions were primarily affected by elevation and aspect. Juniper forest had higher species richness andα-diversity and lowerβ-diversity in the herb layer of the understory plant community than spruce forest, suggesting that the former may be more important in maintaining understory biodiversity and community stability in alpine coniferous forest ecosystems.

scholarly journals Fuel load, stand structure, and understory species composition following prescribed fire in an old-growth coast redwood (Sequoia sempervirens) forest

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
David Cowman ◽  
Will Russell
Keyword(s):  
Species Composition ◽  
Prescribed Burning ◽  
Sequoia Sempervirens ◽  
Anthropogenic Sources ◽  
Fuel Load ◽  
Old Growth ◽  
Understory Species ◽  
Coast Redwood ◽  
Understory Species Composition ◽  
Redwood Forests

Abstract Background With the prevalence of catastrophic wildfire increasing in response to widespread fire suppression and climate change, land managers have sought methods to increase the resiliency of landscapes to fire. The application of prescribed burning in ecosystems adapted to fire can reduce fuel load and fire potential while minimizing impacts to the ecosystem as a whole. Coast redwood forests have historically experienced fire from both natural and anthropogenic sources, and are likely to respond favorably to its reintroduction. Results Random sampling was conducted in three burned sites and in three unburned sites, in an old-growth coast redwood (Sequoia sempervirens [D. Don] Endl.) forest. Data were collected on fuel, forest structure, and understory species composition and compared between treatments. Downed woody fuel, duff depth, litter depth, and density of live woody fuels were found to be significantly lower on sites treated with fire compared to unburned sites. Density of the dominant overstory canopy species, coast redwood and Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco), remained consistent between treatments, and the abundance of herbaceous understory plant species was not significantly altered by burning. In addition, both downed woody fuel and live fuel measures were positively correlated with time since last burn, with the lowest measures on the most recently burned sites. Conclusions Our results indicated that the use of prescribed burning in old-growth redwood forests can provide beneficial reductions in live and dead surface fuels with minimal impacts to overstory trees and understory herbaceous species.

Understory species composition and production in old-growth western hemlock – Sitka spruce forests of southeastern Alaska

1997 ◽  
Vol 75 (4) ◽  
pp. 574-580 ◽  
Author(s):  
Thomas A. Hanley ◽  
Ward W. Brady
Keyword(s):  
Species Composition ◽  
Tsuga Heterophylla ◽  
Picea Sitchensis ◽  
Thuja Plicata ◽  
Stand Age ◽  
Soil Drainage ◽  
Site Factors ◽  
Old Growth ◽  
Understory Species ◽  
Understory Species Composition

Vascular understory species composition and production were studied in 36 stands in both northern and southern portions of southeastern Alaska, United States. Understory composition and production were related to site factors of soil drainage and slope and overstory factors of species composition, stand age, canopy coverage, and mass (net wood volume). Principal floristic gradients were dominated by differences in production of Alaska blueberry (Vaccinium alaskaense How.), skunk-cabbage (Lysichiton americanum Huit. & St. John), and lady fern (Athyrium filix-femina (L.) Roth). Soil drainage was the principal environmental factor determining understory species composition. Soil drainage also determined overstory mass and, consequently, total understory production, presumably through effects of overstory mass on light interception. Well-drained sites were more productive of trees and less productive of understory than were poorly drained sites. Relations between windthrow, soil drainage, overstory mass, and understory species composition and production are interactive in these excessively wet, old-growth forests. Key words: plant communities, biomass, forest overstory, temperate rain forest, Tsuga heterophylla, Picea sitchensis, Thuja plicata, western red cedar.

The long-term impact of low-intensity surface fires on litter decomposition and enzyme activities in boreal coniferous forests

2016 ◽  
Vol 25 (2) ◽  
pp. 213 ◽  
Author(s):  
Kajar Köster ◽  
Frank Berninger ◽  
Jussi Heinonsalo ◽  
Aki Lindén ◽  
Egle Köster ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Enzymatic Activity ◽  
Litter Decomposition ◽  
Forest Fires ◽  
Biological Activities ◽  
Coniferous Forest ◽  
Fire Disturbance ◽  
Coniferous Forests ◽  
Long Term Impact

In boreal forest ecosystems fire, fungi and bacteria, and their interactions, have a pronounced effect on soil carbon dynamics. In this study we measured enzymatic activities, litter decomposition rates, carbon stocks and fungal and microbial biomasses in a boreal subarctic coniferous forest on a four age classes of non-stand replacing fire chronosequence (2, 42, 60 and 152 years after the fire). The results show that microbial activity recovered slowly after fire and the decomposition of new litter was affected by the disturbance. The percent mass loss of Scots pine litter increased with time from the last fire. Slow litter decomposition during the first post-fire years accelerates soil organic matter accumulation that is essential for the recovery of soil biological activities. Fire reduced the enzymatic activity across all the enzyme types measured. Carbon-degrading, chitin-degrading and phosphorus-dissolving enzymes showed different responses with the time elapsed since the fire disturbance. Microbial and enzymatic activity took decades before recovering to the levels observed in old forest stands. Our study demonstrates that slower post-fire litter decomposition has a pronounced impact on the recovery of soil organic matter following forest fires in northern boreal coniferous forests.

scholarly journals On Estimating Wet Canopy Evaporation from Deciduous and Coniferous Forests in the Asian Monsoon Climate

2012 ◽  
Vol 13 (3) ◽  
pp. 950-965 ◽  
Author(s):  
Minseok Kang ◽  
Hyojung Kwon ◽  
Jung Hwa Cheon ◽  
Joon Kim
Keyword(s):  
Eddy Covariance ◽  
Land Surface ◽  
Deciduous Forest ◽  
Coniferous Forest ◽  
Lookup Table ◽  
Coniferous Forests ◽  
Surface Model ◽  
Monsoon Climate ◽  
Gap Filling ◽  
Infiltration Capacity

Abstract Continuous and direct measurement of evapotranspiration (ET) by the eddy covariance (EC) technique is still a challenge under monsoon climate because of a considerable amount of missing data during the long rainy periods and the consequential gap-filling process. Under such wet canopy conditions, especially in forests, evaporation of the intercepted precipitation (EWC) contributes significantly to the total ET. To quantify the role of EWC, leaf wetness has been measured at multiple levels in the canopy simultaneously with eddy covariance measurements at the KoFlux Gwangneung deciduous and coniferous forests for the entire year from September 2007 to August 2008. In this study, the measured EWC and the controlling mechanism during the wet canopy conditions have been scrutinized. Based on the evaluation of the four different algorithms of EWC estimation, that of the variable infiltration capacity (VIC) land surface model (LSM) has been adopted. All the missing EWC data are then recalculated by using the algorithm of VIC LSM and compared against the traditionally gap-filled EWC data based on the modified lookup table (MLT) method. The latter consistently underestimated EWC on average by 39% in deciduous forest and by 28% in coniferous forest. Major causes of such differences were due to the failure of considering aerodynamic coupling, advection of sensible heat, and heat storage in the MLT-based gap-filling method. Accordingly, a new gap-filling strategy for EWC is proposed that takes proper controlling mechanisms into account.

A new find of macrofossils of Picea crassifolia Kom. in early–middle Holocene sediments of the Qinghai Lake basin and its paleoenvironmental significance

2018 ◽  
Vol 90 (2) ◽  
pp. 310-320 ◽  
Author(s):  
Ruijie Lu ◽  
Xiaokang Liu ◽  
Zhiqiang Lü ◽  
Lu Chen ◽  
Jing Du
Keyword(s):  
Woody Debris ◽  
Coniferous Forest ◽  
Qinghai Lake ◽  
Lake Basin ◽  
Spruce Forest ◽  
Picea Crassifolia ◽  
Middle Holocene ◽  
Qinghai Spruce ◽  
Qinghai Lake Basin ◽  
Growth And Reproduction

AbstractHere we report a new find of abundant woody debris and cones in stratum of two sections located to the east of the Qinghai Lake basin in China. Analysis of the anatomical structure of the wood and cones confirmed that they are Picea crassifolia Kom. The results of accelerator mass spectrometry 14C dating indicate that the buried Qinghai spruce grew during 9.7–4.2 ka, and the ages of the large trunks or branches are mainly concentrated within the interval 7.5–6.5 ka. This finding gives direct evidence at the species level about the presence of coniferous forest in the early–middle Holocene in Qinghai lake basin. In addition, the buried cones suggest that the early-middle Holocene environment was suitable for the propagation of Picea crassifolia Kom. The variations in the occurrence of Qinghai spruce forest in the Holocene probably reflect changes in humidity/moisture. The humid early-middle Holocene was suitable for the growth and reproduction of Qinghai spruce forest, while a shift toward an increasingly arid climate during the late Holocene resulted in the disappearance of Picea crassifolia Kom. from the Qinghai Lake basin, although human activities may also have contributed to the environmental change.

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