Forest structure and regeneration of the Tertiary relict Taiwania cryptomerioides in the Gaoligong Mountains, Yunnan, southwestern China

2015 ◽  
Vol 45 (1) ◽  
pp. 135-155 ◽  
Author(s):  
Long-Yuan He ◽  
Cindy Q. Tang ◽  
Zhao-Lu Wu ◽  
Huan-Chong Wang ◽  
Masahiko Ohsawa ◽  
...  
Keyword(s):  
Forest Structure ◽  
Forest Floor ◽  
Forest Canopy ◽  
Age Classes ◽  
Old Growth ◽  
Old Growth Forests ◽  
Competition For Light ◽  
Taiwania Cryptomerioides ◽  
Steep Slopes ◽  
Survival Mechanisms

We studied forests containing Taiwania cryptomerioides of various ages and habitats on the eastern slopes of the Gaoligong Mountains in terms of forest structure and composition, population structure (size, age), regeneration patterns, and persistence of the species in relation to their favored habitats. Taiwania thrives in unstable habitats on riverbanks in deep valleys, on steep slopes, on cliffs, on roadsides and by mountain paths at the altitudes of 1175-2500 m a.s.l. All these locations were subject to frequent landslides, whereas Taiwania was very rare at similar altitudes on stable gentle slopes or on mountain ridges free of major disturbances. The maximum age of Taiwania was calculated to be c. 1,872 yr, with 358 cm DBH (diameter at a height of 1.3 m) and 70 m high. The size and age classes of Taiwania in old-growth forests were multimodal, indicating that the regeneration varied by chance, depending on disturbances. In the old-growth forests where above-ground competition for light was intense, shade-intolerant and long-lived coniferous Taiwania became emergent (40–70 m), rising above a forest canopy comprised of more shade-tolerant evergreen broad-leaved trees. The reproduction of the species was mainly by means of minute wind-dispersed seeds falling into rock crevices on cliffs or a rocky forest floor, or on disturbed sites. These populations depended on disturbances or gap regeneration to survive. Taiwania gave way to evergreen broad-leaved tree species of Lithocarpus, Cyclobalanopsis, and Manglietia, and to other conifers such as Tsuga dumosa, where landslides were infrequent. Our results provide insights into the ecological characteristics and survival mechanisms of this East Asian paleoendemic conifer, and contribute to our understanding of the differentiation of forests.

Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

2011 ◽  
Vol 41 (1) ◽  
pp. 195-210 ◽  
Author(s):  
Alison Cross ◽  
Steven S. Perakis
Keyword(s):  
Tree Species ◽  
Forest Floor ◽  
Mineral Soil ◽  
Soil Nutrient ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Coast Range ◽  
Old Growth ◽  
Oregon Coast Range ◽  
Old Growth Forests

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.

scholarly journals How Much Can We See from a UAV-Mounted Regular Camera? Remote Sensing-Based Estimation of Forest Attributes in South American Native Forests

2021 ◽  
Vol 13 (11) ◽  
pp. 2151
Author(s):  
Alejandro Miranda ◽  
Germán Catalán ◽  
Adison Altamirano ◽  
Carlos Zamorano-Elgueta ◽  
Manuel Cavieres ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mixed Models ◽  
Forest Canopy ◽  
Complex Structure ◽  
Boosted Regression Trees ◽  
Tree Level ◽  
Old Growth ◽  
Individual Tree ◽  
Native Forests ◽  
Old Growth Forests

Data collection from large areas of native forests poses a challenge. The present study aims at assessing the use of UAV for forest inventory on native forests in Southern Chile, and seeks to retrieve both stand and tree level attributes from forest canopy data. Data were collected from 14 plots (45 × 45 m) established at four locations representing unmanaged Chilean temperate forests: seven plots on secondary forests and seven plots on old-growth forests, including a total of 17 different native species. The imagery was captured using a fixed-wing airframe equipped with a regular RGB camera. We used the structure from motion and digital aerial photogrammetry techniques for data processing and combined machine learning methods based on boosted regression trees and mixed models. In total, 2136 trees were measured on the ground, from which 858 trees were visualized from the UAV imagery of the canopy, ranging from 26% to 88% of the measured trees in the field (mean = 45.7%, SD = 17.3), which represented between 70.6% and 96% of the total basal area of the plots (mean = 80.28%, SD = 7.7). Individual-tree diameter models based on remote sensing data were constructed with R2 = 0.85 and R2 = 0.66 based on BRT and mixed models, respectively. We found a strong relationship between canopy and ground data; however, we suggest that the best alternative was combining the use of both field-based and remotely sensed methods to achieve high accuracy estimations, particularly in complex structure forests (e.g., old-growth forests). Field inventories and UAV surveys provide accurate information at local scales and allow validation of large-scale applications of satellite imagery. Finally, in the future, increasing the accuracy of aerial surveys and monitoring is necessary to advance the development of local and regional allometric crown and DBH equations at the species level.

scholarly journals Observing and Modeling the Vertical Wind Profile at Multiple Sites in and above the Amazon Rain Forest Canopy

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Raoni Aquino Silva de Santana ◽  
Cléo Quaresma Dias-Júnior ◽  
Roseilson Souza do Vale ◽  
Júlio Tóta ◽  
David Roy Fitzjarrald
Keyword(s):  
Forest Structure ◽  
Forest Floor ◽  
Amazon Basin ◽  
Forest Canopy ◽  
Wind Profile ◽  
Vertical Wind ◽  
Average Height ◽  
Dense Forest ◽  
Amazon Rain Forest ◽  
Input Variables

We analyzed the vertical wind profile measured at six experimental tower sites in dense forest in the Amazon Basin and examined how well two simple models can reproduce these observations. In general, the vertical wind profile below the canopy is strongly affected by the forest structure. From the forest floor to 0.65h (where h = 35 m is the average height of the forest canopy for sites considered), the wind profile is approximately constant with height with speeds less than 1 ms−1. Above 0.65 to 2.25h, the wind speed increases with height. Testing these data with the Yi and Souza models showed that each was able to reproduce satisfactorily the vertical wind profile for different experimental sites in the Amazon. Using the Souza Model, it was possible to use fewer input variables necessary to simulate the profile.

scholarly journals Forest structural parameters and aboveground biomass in old-growth and secondary forests along an elevational gradient in Mexico

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Martina Alrutz ◽  
Jorge Antonio Gómez Díaz ◽  
Ulf Schneidewind ◽  
Thorsten Krömer ◽  
Holger Kreft
Keyword(s):  
Climate Change ◽  
Forest Structure ◽  
Aboveground Biomass ◽  
Basal Area ◽  
Elevational Gradient ◽  
Stem Density ◽  
Secondary Forests ◽  
Old Growth ◽  
Old Growth Forest ◽  
Old Growth Forests

Background: Tropical montane forests are important reservoirs of carbon and biodiversity but are threatened by deforestation and climate change. It is important to understand how forest structure and aboveground biomass change along gradients of elevation and succession. Questions: What are the interactive effect of elevation and two stages of succession on forest structure parameters? Studied species: Tree communities. Study site and dates: Cofre de Perote, Veracruz, Mexico. August to December 2015. Methods: We studied four sites along an elevational gradient (500, 1,500, 2,500, and 3,500 m). At each elevation and each forest type, we established five 20 × 20 m plots (n = 40 plots). Within each plot, we measured stem density, mean diameter at breast height (dbh), and tree height and derived basal area and aboveground biomass (AGB). Results: AGB peaked at 2,500 m and was significantly related to elevation and succession, with higher values in old-growth forests than in secondary forests at higher altitudes. Lower values of mean dbh and basal area were found at higher elevations. At the lowest elevation, both successional stages had the same values of stem density and AGB. At both lower elevations, secondary forests had higher values of dbh and basal area. There were high biomass stocks in the old-growth forest at 2,500 and 3,500 m. Conclusions: Old-growth forests at higher elevations are threatened by deforestation, consequently these remaining fragments must be preserved because of their storage capacity for biomass and their ability to mitigate climate change.

Changes in bryophytes assemblages along a chronosequence in eastern boreal forest of Quebec

2018 ◽  
Vol 48 (7) ◽  
pp. 821-834 ◽  
Author(s):  
C. Boudreault ◽  
M. Paquette ◽  
N.J. Fenton ◽  
D. Pothier ◽  
Y. Bergeron
Keyword(s):  
Functional Traits ◽  
Boreal Forests ◽  
Basal Area ◽  
Functional Trait ◽  
Species Dispersal ◽  
Age Classes ◽  
Old Growth ◽  
Forest Continuity ◽  
Old Growth Forests ◽  
Managed Landscapes

Old-growth forests are often considered as biodiversity hotspots for bryophytes because of their diversity in environmental niches or microhabitats and forest continuity. Following this hypothesis, old-growth forests would be expected to house species and functional traits associated with species dispersal different from mature forests. In this study, we compared bryophytes in old-growth and younger forests in terms of species composition, functional trait values, and microhabitat associations. We studied bryophytes in 22 sites distributed across three age classes (18 to >200 years) in boreal forests (eastern Quebec). Richness of liverworts, vegetative-reproducing species, and species with infrequent sexual reproduction were higher in the oldest age class. Species richness was best explained by the availability of coarse woody material (CWM) and other microhabitats, and community structure was best explained by balsam fir basal area. Microhabitats most often associated with indicator species were organic matter, CWM, and pits. Our results indicate that communities associated with older forests are potentially sensitive to forest management as they differ in composition and functional traits from other age classes, with many species characterized by reduced dispersal capabilities and tolerance to competition. An approach that combines critical source habitat protection for dispersal-limited species with protection of critical microhabitats in neighboring managed stands are necessary to allow successful recolonization and maintain bryophyte diversity in managed landscapes.

Spatial variability of the net ecosystem production and its component fluxes across a managed boreal forest landscape in Sweden: A biometric and chamber data-based analysis

2020 ◽  
Author(s):  
Eduardo Martínez García ◽  
Mats B. Nilson ◽  
Hjalmar Laudon ◽  
Jörgen Wallerman ◽  
Johan E.S. Fransson ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Boreal Forest ◽  
Forest Floor ◽  
Forest Landscape ◽  
Northern Sweden ◽  
Age Classes ◽  
Old Growth ◽  
Ecosystem Production ◽  
Spruce Stands ◽  
Forest Floor Vegetation

<p>A managed boreal forest landscape is a diverse successional mosaic of clear-cuts to old-growth stands of different species growing on a variety of soil types. Consequently, this high spatial heterogeneity strongly impacts the forest net ecosystem production (NEP) across the managed landscape. However, the quantification of the variability of NEP and its component fluxes across forested landscapes is currently highly uncertain due to the complex interactions between forest structure and physiological processes and their changes over time.</p> <p>Here, we assessed the spatial variability of NEP and its component fluxes during a 3-year period (2016-2018) over a boreal forest landscape (<em>ca.</em> 68 km<sup>2</sup>) located within the Krycklan catchment (64°14′N, 19°46′E) in northern Sweden. For this purpose, we selected 50 representative forest plots (10 m radius) across the catchment spanning various tree species (pine- and spruce-dominated stands) and forest age classes (from clear-cuts to old-growth forests). In each plot, forest floor CO<sub>2</sub> fluxes were manually measured with custom-made closed chambers in monthly intervals during the growing seasons 2016-2018. Measurements were carried out across natural (both light/dark measurements) and trenching/vegetation removal plots (0.45 × 0.45 m) to partition the net forest-floor exchange (NE<sub>FF</sub>) into its contributing components, i.e., gross primary production (GPP<sub>FF</sub>) and respiration (ER<sub>FF</sub>). ER<sub>FF</sub> was further separated into plant autotrophic and soil heterotrophic respiration (Ra<sub>FF</sub> and Rh<sub>FF</sub>). Plot-level biometric measurements were conducted to determine the net primary production of trees and forest floor vegetation (NPP<sub>T</sub> and NPP<sub>FF</sub>) as well as heterotrophic dead wood respiration (decomposition, Rh<sub>DW</sub>). Finally, NEP was calculated as NEP = NPP<sub>T</sub> + NPP<sub>FF</sub> – Rh<sub>FF</sub> – Rh<sub>DW</sub>.</p> <p>Our results showed that NPP<sub>T</sub> consistently increased with forest ageing, while an opposite pattern was observed for NPP<sub>FF</sub>. In general, spruce stands showed lower NPP<sub>T</sub> compared to spruce stands at each given age class. In contrast, pine stands showed consistently higher NE<sub>FF</sub>, GPP<sub>FF</sub>, ER<sub>FF</sub>, Rh<sub>FF</sub>, Ra<sub>FF</sub>, and NPP<sub>FF</sub> compared to spruce stands. The forest floor was a net CO<sub>2</sub> source, which increased with stand age due to the progressive decrease in GPP<sub>FF</sub>, while the ER<sub>FF</sub> remained similar among all the age classes. In addition, an analogous age-related pattern was observed in Rh<sub>FF</sub>. Our findings also depicted an increasing NEP with forest age from about ≈ 54±67 g C m<sup>-2</sup> yr<sup>-1</sup> during the initial stages of development (i.e., 5-30 years-old) to a maximum of ≈ 170±68 g C m<sup>-2</sup> yr<sup>-1</sup> in middle-aged stands (i.e., 60-100 years-old). Higher NEP was generally observed for pine compared to spruce stands. Interestingly, we found that the old-growth forests steadily continue to accumulate C, which is contrary to the common view that they become C neutral or sources.</p> <p>Overall, this comprehensive study improves our understanding of the spatial variability of the C balance over the heterogeneous regional forest landscape in northern Sweden, identifying tree species, forest floor vegetation and forest ageing as key drivers.</p>

Northwest Forest Plan–the first 15 years (1994–2008): status and trends of late-successional and old-growth forests

2011 ◽  
Author(s):  
Melinda Moeur ◽  
Janet L. Ohmann ◽  
Robert E. Kennedy ◽  
Warren B. Cohen ◽  
Matthew J. Gregory ◽  
...  
Keyword(s):  
Old Growth ◽  
Status And Trends ◽  
Old Growth Forests ◽  
Northwest Forest Plan

Alternatives to clearcutting in the old-growth forests of southeast Alaska: study plan and establishment report.

2000 ◽  
Author(s):  
Michael H. McClellan ◽  
Douglas N. Swanston ◽  
Paul E. Hennon ◽  
Robert L. Deal ◽  
Toni L. de Santo ◽  
...  
Keyword(s):  
Old Growth ◽  
Southeast Alaska ◽  
Old Growth Forests ◽  
Study Plan
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