scholarly journals A window of opportunity for climate-change adaptation: easing tree mortality by reducing forest basal area

2016 ◽  
Vol 15 (1) ◽  
pp. 11-17 ◽  
Author(s):  
John B Bradford ◽  
David M Bell
2018 ◽  
Vol 26 (3) ◽  
pp. e014 ◽  
Author(s):  
Ahmad Hosseini ◽  
Seyed M. Hosseini ◽  
Juan C. Linares

Aim of study: Drought and stand structure are major and interconnected drivers of forest dynamics. Water shortage and tree-to-tree competition may interact under the current climate change scenario, increasing tree mortality. In this study, we aimed to investigate climate trends, site and stand structure effects on tree mortality, with the main hypothesis that drought-induced mortality is higher as competition increases.Area of study: Persian oak forests from Zagros Range, western Iran.Material and Methods: We split the study area into 20 topographical units (TUs), based on aspect, slope and elevation. In each TU, three 0.1 ha plots were established to quantify site and stand characteristics, namely the diameter of all trees and shrubs, stand density and basal area, canopy dieback and mortality. In addition, soil profiles were analyzed to obtain physical and chemical soil properties. Six transects 100 m length were established per TU to measure tree-to-tree competition for alive and dead trees.Main Results: The highest mortality rates and crown dieback were found at higher elevations and southern and western aspects. Our findings confirm increasing rates of tree mortality in stands with higher tree density and shallow soils. As regard links between climate change and forest decline, our results suggest that changing forest structure may have a significant impact on dust emission.Research highlights: Despite severe dry years occurred recently the study area, they are not significantly different than those recorded in the past. Stand structure appears as a modulating factor of climate change effects, linked to competition-related tree vulnerability to drought.


2019 ◽  
Vol 65 (4) ◽  
pp. 496-507 ◽  
Author(s):  
Jianwei Zhang ◽  
Kaelyn A Finley ◽  
Nels G Johnson ◽  
Martin W Ritchie

AbstractStand density affects not only structure and growth, but also the health of forests and, subsequently, the functions of forest ecosystems. Here, we integrated dendrochronology and repeated inventories for ponderosa pine research plots to determine whether long-term growth and mortality responded to climate trends and how varying stand density influenced the responses. The plots were established prior to 1975 on existing stands throughout northern California. Although annual temperature increased consistently for the last 65 years, ring-width indices produced by eliminating age and thinning effects failed to detect radial trend regardless of site quality. However, interannual variation for the indices was substantial, reflecting a strong influence of climate on tree growth. Plot-level basal area increments were significantly affected by tree mortality. Stand density index explained most variation of mortality. Lowering stand density enhanced remaining tree growth, reduced mortality, and increased stand resiliency to disturbances and climate change. Besides higher climate moisture indices or lower vapor pressure deficits, any treatments that improve tree vigor and reduce stress will have a similar effect to reducing stand density. Although neither biotic disturbances nor abiotic conditions can be controlled, forest managers can manage stand density appropriately to enhance resilience to climate change and disturbances.


2019 ◽  
Vol 60 (3) ◽  
pp. 177-198
Author(s):  
Yongjoon Kim ◽  
Sung-Eun Yoo ◽  
Ji Won Bang ◽  
Kwansoo Kim ◽  
Donghwan An

2019 ◽  
pp. 77-104 ◽  
Author(s):  
Karla Diana Infante Ramírez ◽  
Ana Minerva Arce Ibarra

The main objective of this study was to analyze local perceptions of climate variability and the different adaptation strategies of four communities in the southern Yucatán Peninsula, using the Social-Ecological System (SES) approach. Four SESs were considered: two in the coastal zone and two in the tropical forest zone. Data were collected using different qualitative methodological tools (interviews, participant observation, and focal groups) and the information collected from each site was triangulated. In all four sites, changes in climate variability were perceived as “less rain and more heat”. In the tropical forest (or Maya) zone, an ancestral indigenous weather forecasting system, known as “Xook k’íin” (or “las cabañuelas”), was recorded and the main activity affected by climate variability was found to be slash-and burn farming or the milpa. In the coastal zone, the main activities affected are fishing and tourism. In all the cases analyzed, local climate change adaptation strategies include undertaking alternative work, and changing the calendar of daily, seasonal and annual labor and seasonal migration. The population of all four SESs displayed concern and uncertainty as regards dealing with these changes and possible changes in the future.


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