scholarly journals Spatial Variability of Throughfall in a Larch (Larix gmelinii) Forest in Great Kingan Mountain, Northeastern China

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 393
Author(s):  
Houcai Sheng ◽  
Tijiu Cai
Keyword(s):  
Spatial Variability ◽  
Boreal Forest ◽  
Boreal Forests ◽  
Temporal Stability ◽  
Canopy Structure ◽  
Terrestrial Ecosystem ◽  
Rainfall Amount ◽  
Larix Gmelinii ◽  
Forest Types ◽  
Area Index

Larix gmelinii forest is one of the dominant forest types in boreal forest and plays a unique eco-hydrological role in the terrestrial ecosystem. However, the throughfall variability in boreal forest ecosystems, which plays a crucial role in regulating hydrology, remains unclear. Here, we investigated the spatial variability and temporal stability of throughfall within a Larix gmelinii forest in the full leaf stage in Great Kingan Mountain, Northeast China, and the effects of rainfall properties and canopy structure on throughfall variability were systematically evaluated. The results indicate that throughfall represented 81.26% of the gross rainfall in the forest. The throughfall CV (coefficient of variation of throughfall) had a significant and negative correlation with the rainfall amount, rainfall intensity, rainfall duration, and distance from the nearest trunk, whereas it increased with increasing canopy thickness and LAI (leaf area index). The correlation analysis suggested that the throughfall variability was mainly affected by the rainfall amount (R2 = 0.7714) and canopy thickness (R2 = 0.7087). The temporal stability analysis indicated that the spatial distribution of the throughfall was temporally stable. Our findings will facilitate a better understanding of the spatiotemporal heterogeneity of throughfall and help the accurate assessment of throughfall and soil water within boreal forests.

Light extinction coefficients specific to the understory vegetation of the southern boreal forest, Quebec

2000 ◽  
Vol 30 (1) ◽  
pp. 168-177 ◽  
Author(s):  
Isabelle Aubin ◽  
Marilou Beaudet ◽  
Christian Messier
Keyword(s):  
Boreal Forest ◽  
Leaf Area Index ◽  
Light Transmission ◽  
Light Availability ◽  
Understory Vegetation ◽  
Light Extinction ◽  
Forest Types ◽  
Area Index ◽  
K Value ◽  
Extinction Coefficients

This study was conducted in six different forest types in Abitibi, Que., (i) to identify the factors that most influence understory light transmission in the southern boreal forest and (ii) to develop light extinction coefficients (k), which could be used to simulate light transmission in the understory. Light availability and understory vegetation (cover, composition, vertical distribution, and leaf area index) were characterized within three strata (0.05-5 m) in a total of 180 quadrats. Calculated k values were based on measured light availability and leaf area index. These values varied among forest types, strata, understory vegetation types, and cover in the upper stratum. The highest k values were generally associated with a dense stratum of Acer spicatum Lam. We developed five sets of k values based on the factors that most affected light transmission. Measured transmission (Tm) was compared with transmission predicted (Tp) from each set of k values. Light transmission predicted using a single k value (mean k = 0.54) underestimated Tm. More accurate predictions were obtained when we used the other four sets of k values. Our results indicate that, in the southern boreal forest, the understory vegetation can be quite heterogeneous and patterns of light transmission cannot be accurately simulated using a unique k value. However, the various sets of k values developed in this study could be used in prediction models of forest dynamics to obtain relatively good predictions of understory light extinction in forest types similar to the ones studied here.

scholarly journals How does a rubber plantation affect the spatial variability and temporal stability of throughfall?

2018 ◽  
Vol 50 (1) ◽  
pp. 60-74 ◽  
Author(s):  
Jiaqing Liu ◽  
Wenjie Liu ◽  
Weixia Li ◽  
Huanhuan Zeng
Keyword(s):  
Spatial Variability ◽  
Large Scale ◽  
Rainfall Intensity ◽  
Southwest China ◽  
Temporal Stability ◽  
Rubber Plantation ◽  
Area Index ◽  
Rainfall Events ◽  
Rain Gauges ◽  
Heavy Rainfall Events

Abstract In Xishuangbanna, southwest China, the large-scale monoculture rubber plantation replaced the primary tropical forest, which changed the regional hydrology processes and biogeochemical cycles. As throughfall was an important component of the forest ecosystem water input, we researched the spatial variability and temporal stability of throughfall in the rubber plantation. We recorded 30 rainfall events by using 90 rain gauges during 2015–2016. We found a highly significant linear relationship between rainfall and throughfall, and a strong power correlation between the peak 30 min rainfall intensity and throughfall. The coefficient of variation for throughfall was significant and negatively correlated with rainfall and rainfall intensity. We also observed that throughfall had a strong spatial autocorrelation that would decrease during heavy rainfall events. The results indicate that the leaf area index did not have a significant relationship with throughfall. However, the lateral translocation of the throughfall in the canopy significantly affected the spatial distribution of the throughfall. Generally, the lower throughfall positions were close to the nearest rubber trunk, and the higher throughfall positions were mostly below the slope. This study contributes to the knowledge of the spatiotemporal heterogeneity of throughfall and helps elucidate the interception processes in the rubber plantation.

scholarly journals Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

2013 ◽  
Vol 10 (12) ◽  
pp. 8233-8252 ◽  
Author(s):  
C. Yue ◽  
P. Ciais ◽  
S. Luyssaert ◽  
P. Cadule ◽  
J. Harden ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Carbon Balance ◽  
Carbon Stock ◽  
Forest Carbon ◽  
Biomass Carbon ◽  
Co2 Fluxes ◽  
Vegetation Model ◽  
Area Index ◽  
Simulation Results

Abstract. Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m−2 yr−1, for biomass carbon ~1000 g C m−2 and for soil carbon ~2000 g C m−2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation results demonstrate that a global vegetation model such as ORCHIDEE is able to capture the essential ecosystem processes in fire-disturbed boreal forests and produces satisfactory results in terms of both carbon fluxes and carbon-stock evolution after fire. This makes the model suitable for regional simulations in boreal regions where fire regimes play a key role in the ecosystem carbon balance.

Patterns of Biogeochemistry in Alaskan Boreal Forests

2006 ◽  
Author(s):  
David W. Valentine ◽  
Knut Kielland
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
General Circulation ◽  
Plant Productivity ◽  
Parent Material ◽  
Forest Types ◽  
Element Cycling ◽  
Soil C ◽  
Growing Seasons ◽  
Data Gap

As the northernmost forest on Earth, boreal forests endure a combination of environmental challenges common only in subalpine forests elsewhere: extremely cold winters, short growing seasons, cold soils, and limited nutrient availability. Consequently, decomposition has lagged plant production, making circumpolar boreal forest soils one of the largest terrestrial reservoirs of carbon (C). Soil organic matter also constitutes a major source of nutrients, particularly nitrogen (N), that promote plant productivity when released during decomposition. If current trends in high-latitude warming continue (Chapter 4), how will accelerated soil C losses from decomposition compare to the C gains from enhanced plant productivity? This remains an open question of great interest to climate modelers seeking to incorporate biological feedbacks into future generations of general circulation models. This chapter builds on earlier chapters on plants (Chapters 11 and 12), herbivores (Chapter 13), and soil microbes (Chapter 14) to describe the patterns and processes of C and N dynamics in Alaska’s boreal forest, paying particular attention to responses of these processes to the interacting influences of disturbance and climatic variations that occur across the landscape and through time. Other nutrients have received less attention in Alaskan research, and that data gap is reflected in this chapter. Interior Alaska’s boreal forest is a patchwork of successional forest types. The major physiographic zones into which we categorize them reflect the contrasting influences of two major disturbance types: fire in upland and lowland areas results in multiple secondary successional pathways, while a more ordered array of forest types results from a combination of primary succession and variation in flooding frequency during succession on active floodplains (Chapter 7). Within each general physiographic zone (uplands and lowlands, floodplains), differences in the postdisturbance environment further influence vegetation establishment, plant species composition, and, ultimately, element cycling. The state factor approach has proven useful in understanding landscape variation in biogeochemistry (Chapter 1; Van Cleve et al. 1991). As with other aspects of ecosystem function, element cycling reflects control exerted by major state factors: climate, parent material, potential vegetation, topography, and time since the most recent disturbance event.

Spatial variability of stand-scale residuals in Ontario’s boreal forest fires

2009 ◽  
Vol 39 (5) ◽  
pp. 945-961 ◽  
Author(s):  
Ajith H. Perera ◽  
Benjamin D. Dalziel ◽  
Lisa J. Buse ◽  
Robert G. Routledge
Keyword(s):  
Spatial Variability ◽  
Boreal Forest ◽  
Forest Fires ◽  
Boreal Forests ◽  
Forest Cover ◽  
Fire Intensity ◽  
Site Conditions ◽  
Linear Mixed Effects ◽  
Ecological Applications ◽  
Live Tree

Knowledge of postfire residuals in boreal forest landscapes is increasingly important for ecological applications and forest management. While many studies provide useful insight, knowledge of stand-scale postfire residual occurrence and variability remains fragmented and untested as formal hypotheses. We examined the spatial variability of stand-scale postfire residuals in boreal forests and tested hypotheses of their spatial associations. Based on the literature, we hypothesized that preburn forest cover characteristics, site conditions, proximity to water and fire edge, and local fire intensity influence the spatial variability of postfire residuals. To test these hypotheses, we studied live-tree and snag residuals in 11 boreal Ontario forest fires, using 660 sample points based on high resolution photography (1:408) captured immediately after the fires. The abundance of residuals varied considerably within and among these fires, precluding attempts to generalize estimates. Based on a linear mixed-effects model, our data did not support the hypotheses that preburn forest cover characteristics, site conditions, and proximity to water significantly affect the spatial variability of stand-scale residuals. The results do indicate, however, that stand-scale residual variability is associated with local fire intensity (strongly) and distance to fire edge (weakly).

scholarly journals Key canopy traits drive forest productivity

2012 ◽  
Vol 279 (1736) ◽  
pp. 2128-2134 ◽  
Author(s):  
Peter B. Reich
Keyword(s):  
Forest Canopy ◽  
Net Primary Productivity ◽  
Nitrogen Concentration ◽  
Canopy Structure ◽  
Terrestrial Ecosystem ◽  
Growing Season ◽  
Carbon Fluxes ◽  
Mean Annual Temperature ◽  
Area Index ◽  
Growing Season Length

Quantifying the mechanistic links between carbon fluxes and forest canopy attributes will advance understanding of leaf-to-ecosystem scaling and its potential application to assessing terrestrial ecosystem metabolism. Important advances have been made, but prior studies that related carbon fluxes to multiple canopy traits are scarce. Herein, presenting data for 128 cold temperate and boreal forests across a regional gradient of 600 km and 5.4°C (from 2.4°C to 7.8°C) in mean annual temperature, I show that stand-scale productivity is a function of the capacity to harvest light (represented by leaf area index, LAI), and to biochemically fix carbon (represented by canopy nitrogen concentration, %N). In combination, LAI and canopy %N explain greater than 75 per cent of variation in above-ground net primary productivity among forests, expressed per year or per day of growing season. After accounting for growing season length and climate effects, less than 10 per cent of the variance remained unexplained. These results mirror similar relations of leaf-scale and canopy-scale (eddy covariance) maximum photosynthetic rates to LAI and %N. Collectively, these findings indicate that canopy structure and chemistry translate from instantaneous physiology to annual carbon fluxes. Given the increasing capacity to remotely sense canopy LAI, %N and phenology, these results support the idea that physiologically based scaling relations can be useful tools for global modelling.

scholarly journals Boreal Forest Songbird Communities of the Liard Valley, Northwest Territories, Canada

The Condor ◽  
2003 ◽  
Vol 105 (1) ◽  
pp. 27-44 ◽  
Author(s):  
Craig S. Machtans ◽  
Paul B. Latour
Keyword(s):  
Boreal Forest ◽  
Northwest Territories ◽  
Boreal Forests ◽  
Bird Community ◽  
Deciduous Forests ◽  
Zonotrichia Albicollis ◽  
Catharus Ustulatus ◽  
Regional Patterns ◽  
Dendroica Coronata ◽  
Spizella Passerina

Abstract Songbird communities in the boreal forest of the Liard Valley, Northwest Territories, Canada, are described after three years of study. Point count stations (n = 195) were placed in six types of forest (mature deciduous, coniferous, and mixedwood; young forests; wooded bogs; clearcuts) in a 700-km2 area. Vegetation characteristics at each station were also measured. Eighty-five species of birds (59 passerine species) occurred in 11 647 detections. Mixedwood forests had the highest richness of songbirds (∼41 species per 800 individuals) of the six forest types, and contained approximately 30% more individuals than nearly pure coniferous or deciduous forests. Species richness and relative abundance was 10–50% lower than in comparable forests farther south and east, and the difference was most pronounced in deciduous forests. Communities were dominated by a few species, especially Tennessee Warbler (Vermivora peregrina), Magnolia Warbler (Dendroica magnolia), Swainson's Thrush (Catharus ustulatus), Yellow-rumped Warbler (Dendroica coronata) and Chipping Sparrow (Spizella passerina). White-throated Sparrow (Zonotrichia albicollis), a dominant species in boreal forests farther south, was notably scarce in all forests except clearcuts. Clearcuts and wooded bogs had the simplest communities, but had unique species assemblages. Canonical correspondence analysis showed that the bird community was well correlated with vegetation structure. The primary gradient in upland forests was from deciduous to coniferous forests (also young to old, respectively). The secondary gradient was from structurally simple to complex forests. These results allow comparisons with other boreal areas to understand regional patterns and help describe the bird community for conservation purposes. Comunidades de Aves Canoras de Bosques Boreales del Valle de Liard, Territorios del Noroeste, Canadá Resumen. Luego de tres años de estudio, se describen las comunidades de aves canoras de bosques boreales del Valle de Liard, Territorios del Noroeste, Canadá. Se ubicaron estaciones de conteo de punto (n = 195) en seis tipos de bosque (maduro caducifolio, conífero y de maderas mixtas; bosques jóvenes; pantanos arbolados; zonas taladas) en un área de 700 km2. Las características de la vegetación en cada estación también fueron medidas. Se registraron 85 especies de aves (59 especies de paserinas) en 11 647 detecciones. Los bosques mixtos presentaron la mayor riqueza de aves canoras (∼41 especies por 800 individuos) de los seis tipos de bosque, y contuvieron aproximadamente 30% individuos más que los bosques de coníferas y los caducifolios. La riqueza de especies y la abundancia relativa fue 10–50% menor que en bosques comparables más al sur y al este, y la diferencia fue más pronunciada en los bosques caducifolios. Las comunidades estuvieron dominadas por unas pocas especies, especialmente Vermivora peregrina, Dendroica magnolia, Catharus ustulatus, Dendroica coronata y Spizella passerina. Zonotrichia albicollis, una especie dominante en bosques boreales más al sur, fue notablemente escasa en todos los bosques, excepto en las zonas taladas. Las áreas taladas y los pantanos arbolados tuvieron las comunidades más simples, pero presentaron ensamblajes únicos. Análisis de correspondencia canónica mostraron que la comunidad de aves estuvo bien correlacionada con la estructura de la vegetación. El gradiente primario en bosques de zonas altas fue de bosque caducifolio a conífero (también de joven a viejo, respectivamente). El gradiente secundario fue de bosques estructuralmente simples a bosques complejos. Estos resultados permiten hacer comparaciones con otros bosques boreales para entender los patrones regionales y ayudar a describir las comunidades de aves con fines de conservación.

scholarly journals Temporal stability of electrical conductivity in a sandy soil

2016 ◽  
Vol 30 (3) ◽  
pp. 349-357 ◽  
Author(s):  
Aura Pedrera-Parrilla ◽  
Eric C. Brevik ◽  
Juan V. Giráldez ◽  
Karl Vanderlinden
Keyword(s):  
Electrical Conductivity ◽  
Spatial Variability ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Precision Agriculture ◽  
Temporal Stability ◽  
Principal Component ◽  
Model Parameters ◽  
Soil Spatial Variability

Abstract Understanding of soil spatial variability is needed to delimit areas for precision agriculture. Electromagnetic induction sensors which measure the soil apparent electrical conductivity reflect soil spatial variability. The objectives of this work were to see if a temporally stable component could be found in electrical conductivity, and to see if temporal stability information acquired from several electrical conductivity surveys could be used to better interpret the results of concurrent surveys of electrical conductivity and soil water content. The experimental work was performed in a commercial rainfed olive grove of 6.7 ha in the ‘La Manga’ catchment in SW Spain. Several soil surveys provided gravimetric soil water content and electrical conductivity data. Soil electrical conductivity values were used to spatially delimit three areas in the grove, based on the first principal component, which represented the time-stable dominant spatial electrical conductivity pattern and explained 86% of the total electrical conductivity variance. Significant differences in clay, stone and soil water contents were detected between the three areas. Relationships between electrical conductivity and soil water content were modelled with an exponential model. Parameters from the model showed a strong effect of the first principal component on the relationship between soil water content and electrical conductivity. Overall temporal stability of electrical conductivity reflects soil properties and manifests itself in spatial patterns of soil water content.

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