Preadaptation and spatial effects on retention-tree survival in cut areas in Estonia

2008 ◽  
Vol 38 (10) ◽  
pp. 2616-2625 ◽  
Author(s):  
Raul Rosenvald ◽  
Asko Lõhmus ◽  
Andres Kiviste

Survival of live retention trees is a key issue for stand-scale applications of natural-disturbance-based silviculture. We explored the survival of 3255 trees in 102 cut areas (mean size 2.3 ha) in Estonia for 6 years, focusing on spatial variation and preadaptation of the trees. Altogether, 35% of the trees died during the study period, contributing 4.4 m3 of downed dead trunks and 1 m3 of standing dead trees per hectare. The annual mortality rates declined over time. The main survival determinants were tree species (higher for hardwood deciduous trees), diameter (species dependent), position relative to forest edge (higher for trees near current or former forest edges), retention density (positive), and exposure (negative). The results suggest that (1) green-tree retention can effectively increase the abundance of large shade-tolerant trees, but it is equally important for producing deadwood; (2) larger individuals, former interior-forest trees near current forest edges, and preadapted trees in open conditions should be preferably retained; (3) there is no obvious necessity to modify tree-retention techniques for tree survival according to geographical region or forest site type.

2015 ◽  
Vol 76 (4) ◽  
pp. 322-330 ◽  
Author(s):  
Konrad Skwarek ◽  
Szymon Bijak

Abstract Dead wood plays an important role for the biodiversity of forest ecosystems and influences their proper development. This study assessed the amount of coarse woody debris in municipal forests in Warsaw (central Poland). Based on the forest site type, dominant tree species and age class, we stratified all complexes of the Warsaw urban forests in order to allocate 55 sample plots. For these plots, we determined the volume of dead wood including standing dead trees, coarse woody debris and broken branches as well as uprooted trees. We calculated the amount of dead wood in the distinguished site-species-age layers and for individual complexes. The volume of dead matter in municipal forests in Warsaw amounted to 38,761 m3, i.e. 13.7 m3/ha. The obtained results correspond to the current regulations concerning the amount of dead organic matter to be left in forests. Only in the Las Bielański complex (northern Warsaw) volume of dead wood is comparable to the level observed in Polish national parks or nature reserves, which is still far lower than the values found for natural forests. In general, municipal forests in Warsaw stand out positively in terms of dead wood quantity and a high degree of variation in the forms and dimensions of dead wood.


2019 ◽  
Vol 11 (22) ◽  
pp. 2614 ◽  
Author(s):  
Nina Amiri ◽  
Peter Krzystek ◽  
Marco Heurich ◽  
Andrew Skidmore

Knowledge about forest structures, particularly of deadwood, is fundamental for understanding, protecting, and conserving forest biodiversity. While individual tree-based approaches using single wavelength airborne laserscanning (ALS) can successfully distinguish broadleaf and coniferous trees, they still perform multiple tree species classifications with limited accuracy. Moreover, the mapping of standing dead trees is becoming increasingly important for damage calculation after pest infestation or biodiversity assessment. Recent advances in sensor technology have led to the development of new ALS systems that provide up to three different wavelengths. In this study, we present a novel method which classifies three tree species (Norway spruce, European beech, Silver fir), and dead spruce trees with crowns using full waveform ALS data acquired from three different sensors (wavelengths 532 nm, 1064 nm, 1550 nm). The ALS data were acquired in the Bavarian Forest National Park (Germany) under leaf-on conditions with a maximum point density of 200 points/m 2 . To avoid overfitting of the classifier and to find the most prominent features, we embed a forward feature selection method. We tested our classification procedure using 20 sample plots with 586 measured reference trees. Using single wavelength datasets, the highest accuracy achieved was 74% (wavelength = 1064 nm), followed by 69% (wavelength = 1550 nm) and 65% (wavelength = 532 nm). An improvement of 8–17% over single wavelength datasets was achieved when the multi wavelength data were used. Overall, the contribution of the waveform-based features to the classification accuracy was higher than that of the geometric features by approximately 10%. Our results show that the features derived from a multi wavelength ALS point cloud significantly improve the detailed mapping of tree species and standing dead trees.


1972 ◽  
Vol 2 (2) ◽  
pp. 127-151 ◽  
Author(s):  
Yoshika Oniki ◽  
Edwin O. Willis

Abstract Birds that prey on arthropods flushed by army ants north of the eastern Amazon were studied at Serra do Navio and Reserva Ducke (Brazil) and at Nappi Creek and Bartica (Guyana). Regular ant-followers are two medium-sized antbirds (Percnostola rufifrons and Gymnopithys rufigula) and two smaller ones (Pithys albifrons and Hylophylax poecilonota), plus five woodcreepers of differing sizes (from very large Hylexetastes perrotti through Dendrocolaptes picumnus, D. certhia, and Dendrocincla merula to medium-sized Dendrocincla fuliginosa). Four other regular ant-followers occur in the region but were not found at the study areas. Forty-five species of casual or nonprofessional ant-followers, including 16 antbirds, 5 woodcreepers, and 5 manakins, also were recorded. Percnostola rufifrons tends to be at the forest edge or in second growth. Pithys albifrons works around Gymnopithys rufigula, Hylophylax poecilonota peripheral to both, in the forest interior. The large Dendrocolaptes picumnus and medium-large Dendrocincla merula often capture prey near the ground, like antbirds. Unlike antbirds, which use vertical or horizontal slender perches, the woodcreepers use thick vertical perches. Dendrocolaptes certhia and Dendrocincla fuliginosa also tend to capture prey high over the ground-foraging antbirds. The woodcreepers tend to forage lower at midday. Hylexetastes perrotti is rare, and overlaps strongly with D. picumnus. There is fairly large overlap among the 9 professional ant-followers, and large ones chase away smaller ones. Nonprofessional birds tend to forage briefly or peripherally when or slightly after the professional species are active. They also forage above the antbirds and below or above the woodcreepers, and concentrate at forest edges or in second growth. The guild of ant-following birds in this region differs fairly widely from guilds in Panamá and at Belém, Brazil; the absence of large antbirds and the predominance of large woodcreepers north of the Amazon are the major differences.


Wetlands ◽  
2017 ◽  
Vol 38 (1) ◽  
pp. 133-143 ◽  
Author(s):  
Mary Jane Carmichael ◽  
Ashley M. Helton ◽  
Joseph C. White ◽  
William K. Smith

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Sutedjo Sutedjo ◽  
Warsudi Warsudi

 Akasia mangium (Acacia mangium Willd) bukan tumbuhan asli Kalimantan namun sejak puluhan tahun tumbuh berkembang pesat di berbagai wilayah Kalimantan termasuk Kalimantan Timur. Dikenal sebagai tumbuhan yang mampu tumbuh di lahan kritis sehingga pada awal tahun 1990-an dijadikan tanaman  reboisasi sekaligus pengendali alang-alang di wilayah kritis hutan penelitian dan pendidikan Universitas Mulawarman di Bukit Soeharto. Mengherankan, bahwa beberapa tahun taerkhir sebagian praktisi kehutanan dan reklamasi pascatambang merasa gamang menggunakan A. mangium, khawatir jika jenis tersebut akan benar benar menjadi spesies invasif.  Gejala untuk menolak bahkan menghindari  A. mangium sebagai komoditas kehutanan terutama sebagai jenis pengendali lahan kritis mulai meluas. Untuk mengetahui seberapa benar anggapan Acacia mangium sebagai jenis invasif maka dilakukan evaluasi dengan melakukan analisis vegetasi terhadap 3 ha tegakan hutan A. mangium yang ditanam di Bukit Soeharto sebagai uji petik yang saat sekarang telah berumur sekitar 25 tahun. Hasil evaluasi membuktikan bahwa jumlah tanaman per ha (kerapatan) pohon A. mangium menurun (kurang dari jumlah saat ditanam atau sekitar 800 individu/ha). Jumlah yang menurun itupun cenderung mengelompok. Sebagian pohon bahkan ditemukan dalam kondisi mati generasi (standing dead trees). Sementara itu jumlah spesies pohon setempat (local trees species) juga mulai muncul di antara tegakan A.mangium. Dengan demikian terbukti  bahwa A. mngium bukanlah tipe invasif  yang sesungguhnya dan tidak ada alasan utuk menolak penggunaannya sebagai tanaman pengendali lahan kritis selama potensi ancaman terjadinya kebakaran lahan hutan dapat dicegah.


2019 ◽  
Vol 80 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Jan Bodziarczyk ◽  
Jerzy Szwagrzyk ◽  
Tomasz Zwijacz-Kozica ◽  
Antoni Zięba ◽  
Janusz Szewczyk ◽  
...  

Abstract The composition and structure of forest stands in the Tatra National Park were examined using data gathered in 2016 and 2017 from 617 circular sample plots (0.05 ha each). The diameter at breast height of all living trees, standing dead trees, snags, and wind throws was measured along with diameters and lengths of fallen logs within the plot boundaries. Tree height was measured for all living trees within the core (0.01 ha) of the sample plots. Using the obtained data, height-diameter curves were calculated for all major tree species and in the case of spruce, the height-diameter relationships were also calculated separately for each of the three elevation zones (up to 1200 m, between 1200 and 1400 m, above 1400 m). For each elevation zone and park protection zone, we also determined the volumes of live and dead trees. The volume of living trees in the Tatra National Park amounted to 259 m3/ha, which was higher than the volume of dead trees (176 m3/ha). Snags constituted the largest part of the dead wood whilst over 97% of the standing dead trees were spruce Picea abies. Among living trees, the share of spruce ranged from 81% in the low elevation zone to 98% in the middle zone. Other significant species in the lower zone were Abies alba (11%) and Fagus sylvatica (4.5%), while in the middle and upper elevation zones only Sorbus aucuparia occurred in significant numbers. Furthermore, in the lower elevation zone, Fagus sylvatica was the only species displaying significantly higher volumes in the ‘strict protection’ zone compared to the other park areas. In the ‘landscape protection’ zone, Picea abies was the most dominant species and the share of other species in the lowest elevation zones calculated based on tree density was smaller than calculated based on tree volume, indicating problems with stand conversion from spruce monoculture to mixed forest.


THE BULLETIN ◽  
2020 ◽  
Vol 5 (387) ◽  
pp. 56-64
Author(s):  
G.J. Sultangazina ◽  
◽  
А.N. Kuprijanov ◽  
О.А. Kuprijanov ◽  
R.S. Beyshov ◽  
...  

The current article presents study results made on the coenoflora of Adonis vernalis L. in Northern Kazakhstan. The materials have been gathered in the course of field research taking into account the literary data. Ontogenesis and age structure of the coenopopulations are provided on the basis of detailed-route studies. The study of age-related stages was carried out on the territory of Northern Kazakhstan (Akmola and North Kazakhstan regions) in 2018-2019. A. vernalis is a short-stem grassy polycarpic plant, it is represented in Northern Kazakhstan by the populations of dry meadows (Kokshetau Upland) and real meadows (the forest-steppe of North Kazakhstan region). Ontogenesis of A. vernalis has three periods and 7 age stages. Plants have low seed productivity. Seeds have a long endogenous peace related to the underdevelopment of a seed germ. A characteristic feature is the presence of a long pregenerative period in plants of the "steppe" type coenopopulations and its reduction in the "meadow" type coenopopulations. There have been studied thirteen coenopopulations of A. vernalis located in Akmola and North Kazakhstan regions. Coenopopulations of A. vernalis are bound to four main habitats: forest edges, meadow steppes, meadows, artificial plantations. By age, young populations are formed on forest edges, and according to the "delta - omega" classification, there are mature coenopopulations. Mature coenopopulations are mostly formed in meadow steppes, but according to the "delta - omega" classification, all coenopopulations are aging. On meadows, there are many young coenopopulations, but according to the "delta - omega" classification, they are all mature. In artificial plantings, the majority of coenopopulations are aging, but according to the "delta - omega" classification, they are all mature. Thus, changes in habitual living conditions lead to the aging of A. vernalis coenopopulations. By density (pcs/100 m2) all populations are divided into three groups: high, medium, low. All forest edge coenopopulations have a high density, in meadow steppes, the density is average, on meadows and in artificial plantings it is low. The recovery index in most coenopopulations is less than one which indicates a low recovery in A. vernalis populations. The range of age stages shows that in most coenopopulations they are normal, the exception is CP-5 (among artificial plantings) which indicates an old stage of the population and possibly its soon elimination.


The Condor ◽  
2000 ◽  
Vol 102 (3) ◽  
pp. 595-600 ◽  
Author(s):  
D. Ryan Norris ◽  
Bridget J. M. Stutchbury ◽  
Trevor E. Pitcher

Abstract We tested whether Hooded Warblers (Wilsonia citrina) avoided abrupt forest edges by radiotracking males breeding in small, isolated forest patches (0.5–2.0 ha) in northwest Pennsylvania. Because territory edges were synonymous with abrupt forest edges in all cases, we compared space use patterns with males radiotracked in a nearby continuous forest (150 ha), where we defined edge from territorial boundaries. Based on the proportion of edge to core area, males in both habitats avoided the area within 20 m of the edge, implying that males responded to the presence of territory edge rather than forest edge. Surprisingly, however, males in isolated fragments used the edge area significantly more than males in continuous forest, even when measured against the relative amount of edge area within each territory. Elevated levels of edge use were not related to distance of nests to edges, nest stage, or time of day. We conclude that the presence of physical edges is not the sole determinant of territorial space use in this species and there are likely additional social factors influencing occupancy rates in small, isolated woodlots. Therefore, definitions of forest-interior species based on edge use need to be reconsidered.


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