The mixed forests of Greece

2001 ◽  
Vol 66 ◽  
Author(s):  
T. Zagas ◽  
T. Tsitsoni ◽  
A. Hatzistathis

Greece  is a mountainous Mediterranean country characterised by a variety of    microenvironments. As a result, a great number of mixed forest types  appear.    These stands are natural by unevenaged stands with a lot of ecological and  social advantages    (as resistance against biotic and abiotic factors) high biodiversity and  aesthetical beauty.    For this reason, these forests must be protected and managed in a  sustainable way, in order to    fulfil their valuable services.    This paper is dealing with the most important and representative  mixed-species stands of    Greece beginning from those existing in the lower elevations (zone of  evergreen broadleaves)    and continuing to the higher ones (zone of boreal conifers).

2013 ◽  
Vol 726-731 ◽  
pp. 4315-4318
Author(s):  
Shu Li Wang ◽  
Chao Ma

Through the manner of field investigation and room experiments, by using software SPSS 13.0, software ArcGis 9.3 and geostatistical analysis tool, the spatial heterogeneity of the soil bulk density under virgin Pinus koraiensis forest, Betula platyphylla and Pinus koraiensis mixed forest (Pinus koraiensis natural regeneration), Betulaplatyphylla and Pinus koraiensis mixed forest (Pinus koraiensis planted) and pure Pinus koraiensis plantation were studied. The characteristics of the spatial heterogeneity of the soil bulk density under different forest types were different, the spatial heterogeneity of the soil bulk density under four forest types were influenced by random factors, but the auto relationship part of the soil bulk density spatial heterogeneity under Betula platyphylla and Pinus koraiensis mixed forests were bigger, and the change distance was smaller than that under pure Pinus koraiensis plantation. The spatial distribution pattern of the soil bulk density under Betula platyphylla and Pinus koraiensis mixed forests was superior to that under pure Pinus koraiensis plantation. The results would provide a theory basis for the recovery and the sustainable management of the Pinus koraiensis forest.


2021 ◽  
Vol 35 ◽  
pp. 00020
Author(s):  
Yulia Sablirova ◽  
Fatimat Tembotova ◽  
Rustam Pshegusov

Based on the results of the studies conducted in the forest areas of the basins of the rivers Belaya and Malaya Laba, there has been compiled a typological scheme of the coniferous and mixed forests of North-Western Caucasus (NWC) which included 21 forest types, that are distributed into 12 groups. The forest stands of the studied forests types is predominantly complex in composition: mixed-age groups, multi-tiered, medium to high productivity, medium to high-density. The forest regeneration is weak or very weak, according to the scale proposed by S. M. Bebia. The data obtained during the research can be used for assessing the dynamics of the forest biogeocenoses, biodiversity, as well as successional processes.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9274
Author(s):  
Yue Pang ◽  
Jing Tian ◽  
Xuan Zhao ◽  
Zhi Chao ◽  
Yuchao Wang ◽  
...  

Background Carbon (C), nitrogen (N) and phosphorus (P) stoichiometric ratios are important indicators of ecosystem function and productivity. However, few studies have assessed the nutrient relationship between plant, litter and soil, and the nutrient stock in different secondary mixed forest types. Methods We investigated the C, N and P concentrations and stoichiometric ratios in trees, understory plants, litter and soil layers in three different secondary mixed forest types (broadleaf mixed forests (BM), broadleaf-conifer mixed forests (BCM) and coniferous mixed forests (CM)) in the Qinling Mountains. Results The results showed that significant differences in C:N:P stoichiometry were detected in multiple organs in the vegetation layers in the different forest types. Trees, shrubs and herbs all allocated more N and P in leaves and had a higher N:P ratio in leaves than in other organs. The C concentrations, C:N ratios and C:P ratios of all tree organs showed a decreasing order: BM < BCM < CM, while the N and P concentrations showed an increasing order: BM > BCM > CM. For litter and soil, BM had generally higher N and P concentrations than those of BCM and CM. The highest N and P stock was in tree branches-not in the stem, which had the highest biomass (except for P in CM). Compared with other forest types, CM stored more nutrients in the labile litter layer, while BM stored more nutrients in the stable soil layer. The net ecosystem nutrient element stock in BM was generally higher than that in BCM and CM. The C, N and P concentrations and stoichiometry in the plant organs, litter and soil were significantly correlated. Conclusion Our findings demonstrate that nutrient concentrations in plant organs, litter and soil are tightly linked in secondary mixed forests.


Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 413
Author(s):  
Lingbo Dong ◽  
Hongyang Wei ◽  
Zhaogang Liu

The fine-scale spatial patterns of trees and their interactions are of paramount importance for controlling the structure and function of forest ecosystems; however, few management techniques can be employed to adjust the structural characteristics of uneven-aged mixed forests. This research provides an accurate, efficient, and impersonal comprehensive thinning index (P-index) for selecting candidate harvesting trees; the index was proposed by weighting the commonly used quantitative indices with respect to stand fine-scale structures, competition status, tree vigor, and tree stability. The applications of the proposed P-index in evaluating and simulating the process of thinning operations were examined using four 1-ha mapped plots with different forest types, namely, natural secondary forest, natural pine-broadleaved mixed forest, natural larch-birch mixed forest, and natural oak forest, which were widely distributed across the Heilongjiang Province in Northeast China. The results indicated that the proposed P-index could effectively affect the structural differentiations between different forest types and alternative thinning intensities. The marginal benefits of alternative thinning intensities on the integrated forest structure indicated that removing 10% of the trees from the plots might be the optimal thinning intensity from the perspective of optimizing stand structure, in which the P-index values could be increased by approximately 5%–11% for the four tested plots. The main conclusion from this paper was that the proposed P-index could be used as a quantitative tool to manage uneven-aged mixed forests.


Author(s):  
Kirsten Höwler ◽  
Torsten Vor ◽  
Peter Schall ◽  
Peter Annighöfer ◽  
Dominik Seidel ◽  
...  

AbstractResearch on mixed forests has mostly focused on tree growth and productivity, or resistance and resilience in changing climate conditions, but only rarely on the effects of tree species mixing on timber quality. In particular, it is still unclear whether the numerous positive effects of mixed forests on productivity and stability come at the expense of timber quality. In this study, we used photographs of sawn boards from 90 European beech (Fagus sylvatica L.) trees of mixed and pure forest stands to analyze internal timber quality through the quality indicator knot surface that was quantitatively assessed using the software Datinf® Measure. We observed a decrease in knot surface with increasing distance from the pith as well as smaller values in the lower log sections. Regarding the influence of neighborhood species identity, we found only minor effects meaning that timber qualities in mixed stands of beech and Norway spruce (Picea abies (L.) H. Karst.) tended to be slightly worse compared to pure beech stands.


2021 ◽  
Vol 13 (13) ◽  
pp. 2508
Author(s):  
Loredana Oreti ◽  
Diego Giuliarelli ◽  
Antonio Tomao ◽  
Anna Barbati

The importance of mixed forests is increasingly recognized on a scientific level, due to their greater productivity and efficiency in resource use, compared to pure stands. However, a reliable quantification of the actual spatial extent of mixed stands on a fine spatial scale is still lacking. Indeed, classification and mapping of mixed populations, especially with semi-automatic procedures, has been a challenging issue up to date. The main objective of this study is to evaluate the potential of Object-Based Image Analysis (OBIA) and Very-High-Resolution imagery (VHR) to detect and map mixed forests of broadleaves and coniferous trees with a Minimum Mapping Unit (MMU) of 500 m2. This study evaluates segmentation-based classification paired with non-parametric method K- nearest-neighbors (K-NN), trained with a dataset independent from the validation one. The forest area mapped as mixed forest canopies in the study area amounts to 11%, with an overall accuracy being equal to 85% and K of 0.78. Better levels of user and producer accuracies (85–93%) are reached in conifer and broadleaved dominated stands. The study findings demonstrate that the very high resolution images (0.20 m of spatial resolutions) can be reliably used to detect the fine-grained pattern of rare mixed forests, thus supporting the monitoring and management of forest resources also on fine spatial scales.


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