Vladan Ivetić

Reforestation challenges in Southeast Europe facing climate change

Projections of the regional climate model for Southeast Europe generally predict an increasing of temperature and a decrease in precipitation, with some local variations. Higher frequency of extreme weather events and increased flooding can also be expected. This climate change will, among other things, result in changes in habitats and species distribution, and a decrease in biodiversity. In most cases, forest ecosystems will be unable to adapt fast enough to keep pace with changes in climate. Extreme weather events and low precipitation during the growing season will cause high mortality of seedlings after planting. New forests will face the whole range of these changes because of the long lifetime of trees. Reforestation programs must take projections of climate change into consideration. In the long term, new guidelines for site-species matching, provenance selection, and genetic diversity need to be adopted. In the short term, site preparation, planting techniques, and post planting protection need to be improved. In addition, seedling quality (morphological, physiological, and genetic) and planting time need to be specific for each site. New site preparation, planting, and post-planting protection methods are useful tools for short term success measured in seedling survival and initial growth. Seedling quality is essential for short and long term success. Different strategies, such as assisted migration and increased genetic diversity of planting material, can provide better chances for long term success measured in growth, fitness, and capability to produce the next, better adapted generation.

Direct Seeding in Reforestation – A Field Performance Review

Direct seeding has been considered a forest restoration option for centuries. Over the past half century, the use of this practice has declined in developed countries as forest regeneration programs have advanced with the production of quality seedlings that can successfully establish restoration sites. Direct seeding is being reconsidered as a restoration option as the potential size of the worldwide forest restoration program has grown because of massive deforestation in third-world nations and due to global climate change. This review examines direct seeding from a number of perspectives. First, merits of using this practice in restoration programs are defined. Major merits of this option are that it can be done quickly, over hard to reach and large disturbed areas, and at a relatively low cost. Second, current research findings from restoration programs are discussed. The major finding is that seedling establishment rates are low (i.e. typically around 20% of seeds planted) due to site conditions, seed predation and vegetation competition, and field performance (i.e. survival and growth) is lower than planted seedlings. Third, operational practices for the application in restoration programs are reviewed. To successfully conduct direct seeding programs practitioners need to consider seedbed receptivity, seed distribution and seeding rate. Fourth, potential new practices are presented. Some of these new practices attempt to create a more effective means to disperse seed across the site, minimize seed predation or create a more favorable microsite environment. This review provides a synthesis of what is known about direct seeding, thereby allowing practitioners to make a rational decision of whether to apply this practice towards their forest restoration program.

Concerns and evidence on genetic diversity in planted forests

Planted forests are an important source of various services (economic, environmental, and social) with increasing portion in the total world’s forest area. Genetic diversity is fundamental for success and sustainability of planted forests. Facing the concern of the reduction of genetic diversity in planted forests, this study offers a review of evidence on comparisons between the levels of genetic diversity in forests established by different regeneration methods. A total of 34 papers comparing genetic diversity in natural forests versus various regeneration methods of 24 tree species examined by the range of markers are reviewed. In most cases, there are no significant differences in genetic diversity between natural and planted forests, followed by an almost equal number of cases with decreased and increased level of genetic diversity. The loss of rare alleles, but also new alleles are reported in planted forests. Although the origin of planting material in the most cases are unknown, the size of parental population is determinant for the level of genetic diversity in the new forest, with the provenancing and seed collection strategy as the most important management practices in planting projects.

Initial height and diameter are equally related to survival and growth of hardwood seedlings in first year after field planting

This study compares the relation of initial height and root collar diameter of bareroot hardwoods seedlings to survival and growth in first year after planting. A total of six species used in Serbian reforestation programs were tested (four native: Fagus sylvatica, Ulmus laevis, Fraxinus excelsior, and Acer pseudoplatanus and two exotic: Robinia pseudoacacia, and Quercus rubra), at 6 sites with a wide range of environmental conditions. Initial seedling height and diameter were equally related to field performance and better in forecasting growth than survival. The relation between seedlings initial morphological attributes and survival was species specific, while for all tested species growth was positively correlated to seedling size at planting. Although large seedlings kept their advantage in size, smaller seedlings grew at a higher rate. Both initial H and D should be considered as equally important in operational programs for hardwoods seedling quality testing.

Response of rare and endangered species Picea omorika to climate change - The need for speed

Serbian spruce (Picea omorika (Pancic) Purk.) is a rare and endangered tertiary relict and endemic species, with restricted and fragmented natural range in Serbia and Bosnia and Herzegovina, mainly around the mid-course of the Drina river. Since the middle of the 19th century, its natural range declines constantly, followed by a decline in the number of mature individuals. The decline of this forest species is slow and mainly attributed to poor regeneration and low competing ability. Given the foreseen worsening of the climate in forthcoming decades, this decline can only accelerate. In recent years, dieback related to drought has been observed as response to extreme weather events suggesting that Serbian spruce will face difficulties in adapting to climate change within its natural range. However, successful use of Serbian spruce in Central and Northern Europe indicates potentially large adaptive potential of this species which, along with the high genetic variability, outweigh the limited morphological variation, self-fertilization, and limitations related to the restricted natural range in the first place, and, indicates possible directions of migration in the second place. In this paper, current conservation actions are discussed, and strategies for the species survival in a changing environment are suggested. Since migration and adaptation are the least likely responses of this species to climate change, measures such as assisted migration may be the only strategy which will enable persistence of Serbian spruce. Current conservation programs, limited to in-situ actions, need to be supplemented with ex-situ actions and strategies. In the worst case scenario, i.e. for species such as Serbian spruce which are unable to migrate and/or adapt to changing climate, the most suitable sites should be identified and colonized in order to prevent extinction in the near future.

Comparison of seedling quality between autochthonous and poplar clones

Autochthonous poplar species were neglected during the intense establishment of plantations using various selected clones. This paper presents the results of seedlings quality comparison of two autochthonous poplars and three clones of poplar (129/81, I-214 and PE 19/66) in order to determine capabilities for mass production of autochthonous poplar seedlings. The seedlings of clone 129/81 have the largest diameter and height, and the seedlings of black poplar shows the smallest values. Seedlings of gray poplar have similar values as seedlings of clone PE 19/66, except diameter on 1 m above the ground. Clone I–214 shows least values relative to seedlings of other two clones. The results obtained in this study indicate the possibility of mass production of autochthonous poplar seedlings. Considering that the seedlings are used primarily for the purposes of conservation, the existing manufacturing technology, as well as the applicable standards of quality seedlings, which are used for highly productive clones of poplar, should be adapted to the production of a large number of genotypes.

Stocktype effect on field performance of Austrian pine seedlings

Austrian pine (Pinus nigra Arnold) seedlings are one of the most produced planting material in Serbian nurseries. In this study we compared a field performance of two container stocktypes, one usually used (2+0 produced in Plantagrah I) and one recently introduced (1+0 produced in Hiko V120 SS). The trial was established at planting site Vlasko polje (East Serbia), at altitude of 840 m a.s.l., one year following the total destruction of previous pine plantation by ice. One-year-old Austrian pine seedlings produced in Hiko containers show similar initial height and root collar diameter at planting time as two-year-old seedlings produced in traditionally used Plantagrah I containers. There was no vegetation control at field trial during the first growing season. At the end of the first growing season, taller (15.6 cm) and more slender (H/D=4.5) 1+0 seedlings from Hiko containers survived at higher rate, and shorter (10.9 cm) and more stocky seedlings 2+0 produced in Plantagrah I grow in height at higher rate. Seedlings taller at the planting time kept their advantage in size after the first growing season at the field. We found that both stocktypes can be used in operational planting programs on sites with lack of vegetation control.

Interpolation of meteorological data by kriging method for use in forestry

Interpolation is a suitable method of computing the values of a spatial variable at the location which is impossible for measurement, based on the data obtained by the measurement of the same variable at the predetermined locations (e.g. weather stations). In this paper, temperature and rainfall values at 39 weather stations in Serbia and neighbouring countries were interpolated aiming at the research in forestry. The study results are presented in the form of an interactive map of Serbia, which allows a fast and simple determination of the analyzed variable at any point within its territory, which is presented by the example of 27 forest sites.