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Arumae T.,Estonian University of Life Sciences | Lang J.M.,State Forest Management Center
Forestry Studies | Year: 2013

Airborne laser scanner (ALS) measurements from two test sites in Estonia were used to estimate forest canopy-base height (HVL). The ALS data was collected by Estonian Land Board using Leica ALS50-II scanner. The HVL was estimated by using mode value and standard deviation of the ALS pulse reflection position height distribution. The pulse reflections which had height less than 0.5 m over the estimated digital terrain model were excluded from the analysis. In situ measurements of canopy base height (HVA) were carried out in 20 mesotrophic Norway spruce and silver birch forest stands in Järvselja and in 45, mostly Scots pine dominant, mesotrophic forest stands in Aegviidu. Determination coefficients of linear regression between HVL and HVA for both test sites were over 0.8 and the residual standard errors of the models were less than two meters. The influence of forest understory vegetation to the estimation of HVL was tested by excluding the near-to-ground vegetation reflections which had height less than 1.5 m. The test results revealed no significant impact of forest understory to the HVL models. The cross validation showed that the HVL models were independent of test sites and tree species composition. The Järvselja data based HVL model had 1.3 m negative bias if applied to Aegviidu forests and the Aegviidu data based HVL model had 1.4 m positive bias if applied to Järvselja forests. In the Aegviidu test site, difference of HVL models of coniferous and deciduous stands was tested and the difference was found not to be significant. Source


Tilk M.,Estonian University of Life Sciences | Mandre M.,Estonian University of Life Sciences | Kloseiko J.,Estonian University of Life Sciences | Koresaar P.,State Forest Management Center
Journal of Forest Research | Year: 2011

Ecosystems on dunes are influenced by critical environmental factors (mineral nutrients, water deficiency, etc.) considered decisive for their existence. The present paper is based on studies carried out on dunes on the coastal area of the Baltic Sea, southwest Estonia. The nature of forest ecosystems on dunes was studied from the aspects of chemical characteristics of soil, vascular plant species richness and diversity. Sampling sites on the dunes with different heights were selected in Cladina and in Vaccinium vitis-idaea site-type Scots pine forests. Vascular plant species richness and diversity were related to edaphic gradients. On the dune with a height of 32.1 m a.s.l., significant relationships were revealed between the number of species of ground vegetation, pH, volumetric water content in soil and the position of the sample plots. No relationships were revealed between the number of vascular plant species, soil pH, volumetric water content and mineral nutrients on the dune with a height of 9 m a.s.l. The most frequent and abundant plant species on the higher dune were Deschampsia flexuosa, Vaccinium vitis-idaea and V. myrtillus; the highest number of species were found at the bottom of the dune, while on the top only some xeromorphic species such as Festuca ovina, Sedum acre and Crepis tectorum occurred. On the lower dune, the most frequent were Vaccinium vitis-idaea,V. myrtillus and Melampyrum pratense, while V. uliginosum was found only on the bottom and slope and Empetrum nigrum on the top of the dune. © 2011 The Japanese Forest Society and Springer. Source


Kund M.,Estonian University of Life Sciences | Vares A.,State Forest Management Center | Sims A.,Estonian University of Life Sciences | Tullus H.,Estonian University of Life Sciences | Uri V.,Estonian University of Life Sciences
European Journal of Forest Research | Year: 2010

Eight-year-old plantations (11) of silver birch were studied on abandoned agricultural land in Estonia. Trees were planted on uncovered soil and on polyethylene. After eight growing seasons, the height and diameter at breast height of the trees grown on polyethylene were significantly (P < 0.001) larger than corresponding parameters of the trees grown on uncovered soil. The annual height increment of the birches grown on the polyethylene was significantly (P < 0.05) larger during six growing seasons after planting compared to that of the trees grown on uncovered soil. However, annual height increments were not significantly different in the 7th and the 8th growing seasons. The use of polyethylene mulching had a statistically significant effect (P < 0.001) on the height of the beginning of the live crown in 8-year-old plantations. The differences between the values of live crown ratio of the trees grown on polyethylene and the values of live crown ratio of the trees grown on uncovered soil decreased during six growing seasons. However, by the 7th and 8th growing seasons, there was no significant difference (P > 0.05) between the values of the live crown ratio. The height growth of silver birch grown without mulching as well as with mulching was found to be more intensive on Glossic Podzoluvisol, Calcaric Cambisol, Calcaric Luvisol and Dystric Gleysol; however, the height growth was more intensive on mulched soil. The height growth of the birches was modelled on the single-tree and stand levels for five soil types. © 2010 Springer-Verlag. Source


Lutter R.,Estonian University of Life Sciences | Tullus A.,University of Tartu | Kanal A.,University of Tartu | Tullus T.,Estonian University of Life Sciences | And 2 more authors.
European Journal of Forest Research | Year: 2015

The first silver birch (Betula pendula Roth) plantations aimed at short-rotation forestry (SRF) management were established in Estonia in 1999 on former arable land, as experimental and demonstration areas of this novel land use and silvicultural system. Growth and plant–soil relations in such silver birch plantations have more often been studied at a young age (<10 years), while studies covering the later stages of the rotation period are rare. We used repeated monitoring of soil properties and tree growth in 11 midterm (15-year-old) SRF silver birch plantations to evaluate: (1) growth rate and productivity, (2) impact of soil physico-chemical properties on tree growth and (3) changes in the topsoil chemistry between young and midterm plantations. Growth and yield of midterm silver birch SRF plantations exceeded the best local birch forest yield table values by a factor of about 2. The best growth was observed on former agricultural soils corresponding to Oxalis and Oxalis-Myrtillus forest site types. Available water content in the topsoil layer (0–25 cm) had a significant positive effect on the growth rate of birches, with competitively dominant and medium trees more affected. The topsoil pHKCl (range 3.7–7.1) level had a negative effect on growth rate, especially in suppressed trees. The A-horizon of former agricultural soils had provided sufficient nutrients to ensure high productivity of the trees. During the 13 years between the two monitorings, concentrations of the topsoil total N and available P had remained at the same level, while available K and pHKCl had decreased significantly. © 2015, Springer-Verlag Berlin Heidelberg. Source


Kuresoo A.,Estonian University of Life Sciences | Pehlak H.,Estonian University of Life Sciences | Nellis R.,Estonian Ornithological Society | Nellis R.,State Forest Management Center
Estonian Journal of Ecology | Year: 2011

The paper presents the set-up and development of a common bird monitoring scheme in Estonia in 1983-2010. The point-count survey of widespread terrestrial bird species was undertaken to measure long-term population changes and to produce indicators of the condition of habitat types and the wider environment. The scheme has been mostly run by skilled volunteers of the Estonian Ornithological Society. The method applied is point counting on freechoice routes and without limiting recording distance. In the Estonian scheme, each count route consists of 20 points, with 5-minute stops at least 200 m apart. In total, 143 point count routes have been in use by 89 active birdwatchers and professional ornithologists in the course of 28 years. Yearly abundance indices for 87 bird species were calculated using TRIM software. The most evident changes in bird numbers were the declines detected in 1992-1996 among farmland species, and in 2007-2010 among farmland and woodland species. The long-term population trends (1975-2010) in four countries around the Baltic Sea depend on the migratory strategy of bird species. Among trans-Saharan migrants the proportion of declining species was much higher in comparison with short-distance migrants and sedentary species. A marked difference between these countries was found among sedentary bird species - with up to 2/3 of species with increasing trends in Finland and less than 1/3 in Denmark, Sweden, and Estonia. There is a growing interest in using the results of the scheme both at the national and the international scale (PECBMS). Source

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