Above-ground biomass characteristics of young hybrid aspen (Populus tremula L. x P. tremuloides Michx.) plantations on former agricultural land in Estonia

2009 ◽  
Vol 33 (11) ◽  
pp. 1617-1625 ◽  
Author(s):  
Arvo Tullus ◽  
Hardi Tullus ◽  
Tea Soo ◽  
Linnar Pärn
Silva Fennica ◽  
2018 ◽  
Vol 52 (5) ◽  
Author(s):  
Karin Hjelm ◽  
Lars Rytter

Hybrid aspen ( L. × Michx.) is a deciduous tree species suitable for producing large amounts of renewable biomass during short rotations. Its potential under North European conditions could be largely extended if not only agricultural land but also forest land was used for cultivation. Unfortunately, the knowledge of appropriate forest site conditions and effects of site preparation methods on hybrid aspen establishment is limited. In this paper, two studies that explore these questions are presented. In the first study, the sensitivity to acid soils was tested under greenhouse conditions in two type of soils: a) peat soil limed to certain pH levels (3.4–5.7) and b) collected forest soils where pH varied from 3.9 to 5.3. The lowest pH level resulted in reduced growth, elsewhere no significant differences were found. The second study was applied in the field and investigated the effect of four site preparation methods on survival and growth. The methods were: 1) control with no site preparation, 2) patch scarification, 3) mounding and 4) soil inversion. While no differences were found for survival, mounding was generally the method with the highest growth and patch scarification was least successful. The result was probably an effect of good soil aeration and less competition from vegetation after mounding. The field study also revealed clonal differences in growth performance, which stresses the importance of clone selection prior to planting. The results of these studies indicate that hybrid aspen is less sensitive to variation in pH and site preparation methods compared with other poplar species, as have been found in similar studies.Populus tremulaP. tremuloides


2008 ◽  
Vol 48 (1) ◽  
pp. 53-66 ◽  
Author(s):  
Jürgen Aosaar ◽  
Veiko Uri

Halli lepa, hübriidlepa ja arukase biomassi produktsioon endistel põllumaadel The present study is based on four experimental sites, located in Southern-Estonia: hybrid alder and grey alder plantations located in Põlva county, and two sample plots of silver birch, located in Tartu county. The stand characteristics, above-ground biomass and current annual production (CAP) were estimated in order to evaluate production capacity of different tree species growing on abandoned agricultural lands. Due to fast growth and high biomass production capacity the most promising tree species for short-rotation forestry in Estonia is grey alder. The stem mass in the 13-years-old grey alder and hybrid alder stand was 63.4 t ha-1 and 40.0 t ha-1, respectively. However, the different biomass production is mainly affected by stand densities, 6170 trees per ha and 4080 trees per ha, respectively. During ageing, the differences between the alder stands diminish. At the age of 14, mean height and diameter at breast height were practically equal. Also the mean stem mass in the older, 13-year old stand, is almost equal: 10.3 kg in grey alder stand and 9.8 kg in hybrid alder stand. At a younger age, the mean stem mass was higher in grey alder stand, but later, at the age of 13, the mean stem mass has become almost the same (10.3 kg in grey alder stand and 9.8 kg in hybrid alder stand). The rotation period for hybrid alder is longer than for grey alder and bulk maturity will occur later. Silver birch is also a highly productive tree species and has a prospect for short-rotation forestry. The mean stem mass and annual current increment of 8-year-old silver birch stand was in same the magnitude as in the grey alder stand. Although the average stand diameter and height were lower in the silver birch stand than in the grey alder stand, it is compensated by the higher wood density of birch wood. The number of trees has affected silver birch stand production, the above-ground biomass in the very high density birch stand (35 600 trees per ha) was significantly lower than in the sparse stand (11 600 trees per ha), 22.8 t ha-1 and 31.2 t ha-1, respectively.


2010 ◽  
Vol 52 (1) ◽  
pp. 18-29 ◽  
Author(s):  
Veiko Uri ◽  
Jürgen Aosaar ◽  
Mats Varik ◽  
Merit Kund

Mõningate kiirekasvuliste lehtpuupuistute kasv ja produktsioonivõime endisel põllumaalSeveral studies about stands growing on abandoned agricultural lands are induced by extensive afforestation of agricultural lands and more intensive use of biomass. Overview of above-ground biomass production of grey alder, hybrid alder and silver birch young stands growing on former agricultural areas are presented in current paper. The results of 16- and 6-year period of alders and silver birch stands, respectively, are reported. Above-ground biomass and biomass production of stands were estimated. The growing stock and current annual increment (CAI) of 16-years-old grey alder stand were 250 m3ha-1and 35.6 m3ha-1, respectively. Due to fast growth and high biomass production capacity grey alder is promising tree species for short-rotation forestry in Estonia. Hybrid alder is productive tree although not exceeding the productivity of grey alders. Stem volume and CAI of the 16-years-old hybrid alder stand were 155 m3ha-1and 21 m3ha-1, respectively. Our results supported earlier data reported in literature: rotation period of hybrid alder is longer than for grey alder and CAI of hybrid alder stands culminate later. The productivity of young silver birch stands on abandoned agricultural land is varying in a broad range. One young silver birch stand growing on abandoned agricultural land was involved into study. Growing stock and CAI in 13-years old stand were 118 m3ha-1and 15 m3ha-1, respectively. These values are exceeding respective values of several yield tables of silver birch and biomass production capability of silver birch stands in favourable conditions is high.


2021 ◽  
Vol 13 (13) ◽  
pp. 2488
Author(s):  
Tomáš Bucha ◽  
Juraj Papčo ◽  
Ivan Sačkov ◽  
Jozef Pajtík ◽  
Maroš Sedliak ◽  
...  

Abandoned agricultural land (AAL) is a European problem and phenomenon when agricultural land is gradually overgrown with shrubs and forest. This wood biomass has not yet been systematically inventoried. The aim of this study was to experimentally prove and validate the concept of the satellite-based estimation of woody above-ground biomass (AGB) on AAL in the Western Carpathian region. The analysis is based on Sentinel-1 and -2 satellite data, supported by field research and airborne laser scanning. An improved AGB estimate was achieved using radar and optical multi-temporal data and polarimetric coherence by creating integrated predictive models by multiple regression. Abandonment is represented by two basic AAL classes identified according to overgrowth by shrub formations (AAL1) and tree formations (AAL2). First, an allometric model for AAL1 estimation was derived based on empirical material obtained from blackthorn stands. AAL2 biomass was quantified by different procedures related to (1) mature trees, (2) stumps and (3) young trees. Then, three satellite-based predictive mathematical models for AGB were developed. The best model reached R2 = 0.84 and RMSE = 41.2 t.ha−1 (35.1%), parametrized for an AGB range of 4 to 350 t. ha−1. In addition to 3214 hectares of forest land, we identified 992 hectares of shrub–tree formations on AAL with significantly lower wood AGB than on forest land and with simple shrub composition.


2017 ◽  
Vol 23 (2) ◽  
Author(s):  
AFSHAN ANJUM BABA ◽  
SYED NASEEM UL-ZAFAR GEELANI ◽  
ISHRAT SALEEM ◽  
MOHIT HUSAIN ◽  
PERVEZ AHMAD KHAN ◽  
...  

The plant biomass for protected areas was maximum in summer (1221.56 g/m2) and minimum in winter (290.62 g/m2) as against grazed areas having maximum value 590.81 g/m2 in autumn and minimum 183.75 g/m2 in winter. Study revealed that at Protected site (Kanidajan) the above ground biomass ranged was from a minimum (1.11 t ha-1) in the spring season to a maximum (4.58 t ha-1) in the summer season while at Grazed site (Yousmarag), the aboveground biomass varied from a minimum (0.54 t ha-1) in the spring season to a maximum of 1.48 t ha-1 in summer seasonandat Seed sown site (Badipora), the lowest value of aboveground biomass obtained was 4.46 t ha-1 in spring while as the highest (7.98 t ha-1) was obtained in summer.


2016 ◽  
Vol 13 (11) ◽  
pp. 3343-3357 ◽  
Author(s):  
Zun Yin ◽  
Stefan C. Dekker ◽  
Bart J. J. M. van den Hurk ◽  
Henk A. Dijkstra

Abstract. Observed bimodal distributions of woody cover in western Africa provide evidence that alternative ecosystem states may exist under the same precipitation regimes. In this study, we show that bimodality can also be observed in mean annual shortwave radiation and above-ground biomass, which might closely relate to woody cover due to vegetation–climate interactions. Thus we expect that use of radiation and above-ground biomass enables us to distinguish the two modes of woody cover. However, through conditional histogram analysis, we find that the bimodality of woody cover still can exist under conditions of low mean annual shortwave radiation and low above-ground biomass. It suggests that this specific condition might play a key role in critical transitions between the two modes, while under other conditions no bimodality was found. Based on a land cover map in which anthropogenic land use was removed, six climatic indicators that represent water, energy, climate seasonality and water–radiation coupling are analysed to investigate the coexistence of these indicators with specific land cover types. From this analysis we find that the mean annual precipitation is not sufficient to predict potential land cover change. Indicators of climate seasonality are strongly related to the observed land cover type. However, these indicators cannot predict a stable forest state under the observed climatic conditions, in contrast to observed forest states. A new indicator (the normalized difference of precipitation) successfully expresses the stability of the precipitation regime and can improve the prediction accuracy of forest states. Next we evaluate land cover predictions based on different combinations of climatic indicators. Regions with high potential of land cover transitions are revealed. The results suggest that the tropical forest in the Congo basin may be unstable and shows the possibility of decreasing significantly. An increase in the area covered by savanna and grass is possible, which coincides with the observed regreening of the Sahara.


2021 ◽  
Vol 21 ◽  
pp. 100462
Author(s):  
Sadhana Yadav ◽  
Hitendra Padalia ◽  
Sanjiv K. Sinha ◽  
Ritika Srinet ◽  
Prakash Chauhan

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