We will start the 2013 Field Season. Until then, we do not expect much news.
Some updates from the project will be found here. Our field
excursion in these wonderful forests start with this post.
The first step in this project, funded by the
LDEO Climate Center, allows for the collection of ancient trees from the grand temperate rainforests of northeastern Turkey.
Specifically, we aim to reconstruct historical drought dynamics using tree-ring proxies from broadleaf species in
temperate rainforests of northeastern Turkey (NET). This region is home to a unique temperate rainforests that comprises some of the last
patches of old-growth forest in Eurasia. Despite the existence of several tree ring width chronologies and dendroclimatic reconstructions for
Turkey, paleoclimate records from NET area are scarce. This region of wet climate, surrounded by much drier and even desert lands, is poorly
represented in previous reconstructions. These reconstructions are essential to investigate the potential impact of climate change on these
areas of high biodiversity. Currently anthropogenic threats to these forests (e.g. logging, hydroelectric projects) make our collection urgent
and timely relevant.
Jengis (2nd from lft), Nesibe, and Dario in front of logs from old-growth trees. For scale, Dario is ~ 2 m tall.
Photo: N. Pederson
Once we have established a network of climatically-sensitive tree ring records in northeast Turkey, we will examine the past, present, and
potential future trajectories of the Colchic forest within the study region using an independent network of tree ring reconstructions of
Mountains along the southeastern coast of the Black Sea experience a pronounced lake effect, which together with
orographic precipitation, cause a wetter climate (Fig 1) than surrounding areas. Precipitation can reach over 2000 mm/year
in parts of NET and western Georgia. The temperate Colchic rainforest thrives in this region making it (1) one of the few
temperate rainforests in the world and (2) the most important refugium of Tertiary flora and tree diversity in Western Eurasia (WEA)
(DellaSala, 2011). These forests likely still hold the largest remnant of old growth forest with minimal human influence in WEA making it an
ideal region for dendroecological studies of long-term forest dynamics.
Figure 1 - Annual precipitation (mm/year) in Turkey. The study area, shown by triangle, is located within the wettest
areas of Turkey.
Although several dendroclimatic reconstructions of drought have been developed for several areas of Turkey (Akkemik et al., 2005;
Touchan et al., 2005; Griggs et al., 2007; Akkemik et al., 2008; Kose et al., 2011), most have focused on the drier regions. In
contrast, very little is known about the past climate in the more humid areas of NET because it is not well captured in existing
reconstructions. Thus, it is crucial to reconstruct hydroclimatic conditions for this region. There is much potential for success as
several species have shown a demonstrated potential for dendroclimatic reconstruction for 400 years or more [N. Kose,
personal communication and Kose and Guner (2012)]. On a
to the area in April 2012, we had the opportunity to sample trees
in these temperate rainforests with Dr. Kose and identified two species with a great potential for reconstructing drought (Fig. 2).
Figure 2 - Dario with an old Quercus petrea - Photo: N. Pederson
Although, temperate rainforests would seem more resilient to
climate changes because of their wet and cool climates, drought has been a historical driver of forest structure in
these areas (Kvavadze and Connor 2005) and some trees are very sensitive to drought (Kose and Guner 2012).
Under climate warming and increased climatic fluctuations, moist regions could experience unprecedented rapid
ecological changes (Booth et al. 2012). Long periods of drought might be more stronger drivers for compositional
and structural changes than shorter and more intense ones (Hanson and Weltzin 2000). Our knowledge on how wet
forest ecosystems respond to climate is limited to the range of climate conditions observed during the last 100-150
years, conditions which might be unique compared to those experienced in the past (Nicault et al. 2008; Trouet et
al. 2009). We will implement an improved scale of research using dendrochronology to identify the relationship
between disturbance and drought over centuries by investigating differential climate response of trees and long
lasting effects of past droughts in forest structure and composition. These empirical results will eventually complement a
forest succession modelling approach to examine possible ecological trends under global change. Understanding
the past will contribute useful lessons on the response of these communities to a changing environment.
The diverse temperate rainforest on Murgul Mountain where "Emir loves Tayla 1978" ;) - Photo: N. Pederson
This project focuses on the Colchic rainforest of NE Turkey for three main reasons: i) it is one of the few
temperate rainforests in the world and the most important refugium of Tertiary flora and tree diversity in
Western Eurasia (WEA) (DellaSala 2011) providing a phylogenetically diverse set of species upon which to
carry out our integrative ecological research; ii) it might be the largest remnant of old growth forest with minimal
human influence in WEA, and thus ideal for dendroecological studies of long-term forest dynamics; and iii) it
includes broadleaf and conifers species covering a wide range of tolerance and resistance to drought and shade
leading to differential species-specfic responses to environmental changes.
||Updated: Dec '12