scholarly journals Insights on Forest Structure and Composition from Long-Term Research in the Luquillo Mountains

Forests ◽  
2017 ◽  
Vol 8 (6) ◽  
pp. 204 ◽  
Author(s):  
Tamara Heartsill Scalley
1980 ◽  
Vol 11 (1) ◽  
pp. 12 ◽  
Author(s):  
Yrjo Haila ◽  
Olli Jarvinen ◽  
Risto A. Vaisanen

Author(s):  
Monica Turner ◽  
Winslow Hansen ◽  
Timothy Whitby ◽  
William Romme ◽  
Daniel Tinker

Understanding succession following severe wildfire is increasingly important for forest managers in western North America and critical for anticipating the resilience of forested landscapes to changing environmental conditions. Successional trajectories set the stage for future carbon storage, abundance and distribution of fuels, and habitat for many species. Early successional forests are increasing throughout the West in response to greater fire activity, but few long-term studies have considered succession following stand-replacing wildfires over large areas. The size and heterogeneity of the 1988 Yellowstone fires created novel opportunities to study succession at an unprecedented scale following severe fire, and we have studied the consequences of these fires for >20 years. In 2012, we began a re-sampling effort in long-term vegetation plots within the area burned by the 1988 fires to answer three overarching questions: (1) Are stand structure and function beginning to converge twenty-five years after the Yellowstone Fires, and what mechanisms may contribute to convergence or divergence? Heterogeneity in forest structure was the rule after the 1988 fires, and postfire lodgepole pine (Pinus contorta var. latifolia) densities ranged from zero to >500,000 trees/ha. The post-1988 cohort of lodgepole pine is reaching a time of critical transitions in structure and function. (2) Are plant community composition and species richness converging or diverging across gradients in local fire severity, post-fire lodgepole pine density, elevation and soil type a quarter-century after the 1988 fires? A central objective in our research has been to understand the relative influence of contingent factors (e.g., local fire severity) vs. deterministic factors (e.g., elevation, soils) on postfire ecosystem development, and how these influences may change through time. (3) How do canopy and surface fuels vary across the postfire landscape, and how will the variation in fuels influence potential fire behavior a quarter century post-fire? Field sampling was conducted for this third question during summer 2012, and data analyses and interpretation are in progress. Overall, results from the proposed study will enhance understanding of succession after one of the most notorious fires of the 20th century. Yellowstone’s postfire forests may serve as benchmarks for forests throughout the region and effective sentinels of change for the Rockies.


2019 ◽  
Vol 15 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Junko Morimoto ◽  
Toshihiro Umebayashi ◽  
Satoshi N. Suzuki ◽  
Toshiaki Owari ◽  
Naoyuki Nishimura ◽  
...  

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 295 ◽  
Author(s):  
Yuanyuan Wang ◽  
Jinghua Yu ◽  
Lu Xiao ◽  
Zhaoliang Zhong ◽  
Qiong Wang ◽  
...  

The conservation of species diversity and improvement of forest structure are essential roles of the Natural Reserve Policy and the Natural Forest Protection Program (NFPP) in China. However, the long-term effects of NFPP are still not well-defined, and a natural reserve (Liangshui) and surrounding region were surveyed as a proxy of NFPP for approaching the protection effects. Our results showed that long-term conservation significantly altered the dominant species in the herb layer (80% of species), followed by shrub (58%) and tree layers (50%); there was a 1.6-8.0-fold increase in abundance in Corylus shrubs, Acer trees and Carex grass, but a 1.3–10.0-fold abundance decrease in larch trees, Athyrium herbs and Lonicera shrubs. In contrast, tree species diversity and distribution evenness increased by 31% and 23.4% in the reserve, respectively. Forest protection in the reserve also led to the forest structural alteration with the observation of larger-sized trees and shorter herbs, but relatively sparse forests (smaller tree density). Structural equation modeling manifested that the reserve directly altered forest structure, at a coefficient of 0.854, nearly two-fold higher than its impact on diversity (0.459) and dominant species (−0.445). The most affected parameters were plant size (trees and herbs) and tree density related to forest structure, tree diversity, herb richness and evenness for diversity traits, and Oxalidaceae and Rosaceae for dominant species. This study provides basic data that can be used to evaluate the impact of the nature reserve in NE China, and these findings can be used to guide the implementation of NFPP in the long-term in the future.


2018 ◽  
Vol 38 (4) ◽  
Author(s):  
徐文茹 XU Wenru ◽  
贺红士 HE Hongshi ◽  
罗旭 LUO Xu ◽  
黄超 HUANG Chao ◽  
唐志强 TANG Zhiqiang ◽  
...  

2004 ◽  
Vol 20 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Leslie Finical Halleck ◽  
Joanne M. Sharpe ◽  
Xiaoming Zou Zou

Controls over net primary productivity are the subject of a long-term experiment within a lowland subtropical wet forest in the Luquillo mountains of Puerto Rico. Responses of the fern community to fertilization and debris-removal treatments and to monitoring activities were assessed 6 y after the experiment began in October 1989, just after the passage of Hurricane Hugo. Negative fern responses to fertilization included a qualitative change in species composition and a 13-fold reduction in density compared with controls. Plants were smaller and spore production rates were lower. Debris removal reduced the number of species and increased the proportion of terrestrial species. Density of Nephrolepis rivularis individuals in debris-removal plots was only 5% that of control levels while abundance of Thelypteris deltoidea nearly doubled. Buffer-zone fern density was 36% greater than and per cent of leaves damaged was half that of the monitored zones. The magnitude of the responses of ferns to experimental treatments and to monitoring effects suggest that they may be good early indicators of change in a tropical forest.


eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Julie Morin-Rivat ◽  
Adeline Fayolle ◽  
Charly Favier ◽  
Laurent Bremond ◽  
Sylvie Gourlet-Fleury ◽  
...  

The populations of light-demanding trees that dominate the canopy of central African forests are now aging. Here, we show that the lack of regeneration of these populations began ca. 165 ya (around 1850) after major anthropogenic disturbances ceased. Since 1885, less itinerancy and disturbance in the forest has occurred because the colonial administrations concentrated people and villages along the primary communication axes. Local populations formerly gardened the forest by creating scattered openings, which were sufficiently large for the establishment of light-demanding trees. Currently, common logging operations do not create suitable openings for the regeneration of these species, whereas deforestation degrades landscapes. Using an interdisciplinary approach, which included paleoecological, archaeological, historical, and dendrological data, we highlight the long-term history of human activities across central African forests and assess the contribution of these activities to present-day forest structure and composition. The conclusions of this sobering analysis present challenges to current silvicultural practices and to those of the future.


Sign in / Sign up

Export Citation Format

Share Document