Growth patterns from different forest generations of Scots pine in Estonia     

Sandra Metslaid  Allan Sims  Ahto Kangur  Maris Hordo  Kalev Jõgiste  Andres Kiviste  Pertti Hari 《Journal of Forest Research》2011,16(3):237-243

There is strong evidence that climate change alters tree growth in boreal forests. In Estonia, the analysis of ring measurements has been a common method to study growth changes. In this study, annual height growth data from dominant or co-dominant Scots pine (Pinus sylvestris L.) trees were used to develop a growth model for three forest generations. Stem analysis was applied and annual height growth was measured as the distance between whorls, as detected by branch knots of whorls on the split stem surface. Retrospective analysis of height growth produced comparative trends for three different age groups. Statistical analyses were used to estimate the impact of different factors on growth. Annual height growth was considered the best indicator for detecting possible trends in the growth potential of trees. Study results indicate that three generations (separated by time periods of 30–40 years) showed significant differences in growth patterns caused by shifts in climatic factors and management regimes (anthropogenic and natural disturbances).  相似文献   

Approaches for forest disturbance studies: natural variability and tree regeneration     

Ahto Kangur  Toshiya Yoshida  Yasuhiro Kubota  Marek Metslaid 《Journal of Forest Research》2011,16(3):153-154

  相似文献   

Natural stand structures, disturbance regimes and successional dynamics in the Eurasian boreal forests: a review with special reference to Russian studies     

Ekaterina Shorohova  Timo Kuuluvainen  Ahto Kangur  Kalev Jõgiste 《Annals of Forest Science》2009,66(2):201-201

? This review summarizes early stand-scale studies of pristine forest structures, disturbance regimes and successional patterns carried out in boreal Eurasia. We attempt to reveal, characterize and classify stand dynamic types that can be used as templates for nature-based forest management.

? The studies reviewed demonstrate multiple successional pathways in stand development in all types of pristine forests. All-aged stands driven by small-scale disturbances are formed over successional development of several hundreds of years. This endogenous development can be interrupted by stand-replacing or partial disturbances leading to successions with even-aged or cohort-structured stands, respectively. In Western Europe, the most common disturbances are windthrows, surface fires and fluctuations in moisture regime; in Eastern Europe and Siberia, the most common disturbances are crown and surface fires and insect outbreaks. Type, return interval and severity of disturbances are strongly influenced by the site conditions and successional stage of a stand.

? Based on characteristics of forest stands and disturbance regime, four main types of pristine boreal forest stand dynamics can be distinguished: (1) even-aged, compositional change dynamics, (2) even-aged, mono-dominant dynamics, (3) cohort dynamics and (4) fine-scale gap dynamics. These types can be mimicked in developing scenarios of ecological sustainable forest management in Eurasian boreal forests.

  相似文献   

Natural re‐establishment of Atlantic salmon reproduction and the fish community in the previously heavily polluted River Purtse,Baltic Sea     

Martin Kesler  Mart Kangur  Markus Vetemaa 《Ecology of Freshwater Fish》2011,20(3):472-477

Abstract – The River Purtse was historically a significant Atlantic salmon spawning river in the Gulf of Finland (Baltic Sea). After the establishment of oil shale mining and processing in the catchment area in the late 1920s, the salmon population went extinct. By the 1970s, the river was heavily polluted and the lower reaches lacked any fish fauna. However, since the 1990s, pollution from oil shale mines was greatly reduced and water quality started to improve. The first fish species to repopulate the polluted area were gudgeon and nine‐spined stickleback. The first salmon parr from wild spawning were recorded in 2006. Up to 2009, a total of fifteen fish species have been recorded including trout and the sensitive bullhead. This study illustrates the natural recovery of the fish fauna following water quality improvement.  相似文献