Bohdan Konôpka

Variation in fine root biomass of three European tree species: Beech (Fagus sylvatica L.), Norway spruce (Picea abies L. Karst.), and Scots pine (Pinus sylvestris L.)

Abstract Fine roots (<2 mm) are very dynamic and play a key role in forest ecosystem carbon and nutrient cycling and accumulation. We reviewed root biomass data of three main European tree species European beech, (Fagus sylvatica L.), Norway spruce (Picea abies L. Karst.) and Scots pine (Pinus sylvestris L.), in order to identify the differences between species, and within and between vegetation zones, and to show the relationships between root biomass and the climatic, site and stand factors. The collected literature consisted of data from 36 beech, 71 spruce and 43 pine stands. The mean fine root biomass of beech was 389 g m−2, and that of spruce and pine 297 g m−2 and 277 g m−2, respectively. Data from pine stands supported the hypothesis that root biomass is higher in the temperate than in the boreal zone. The results indicated that the root biomass of deciduous trees is higher than that of conifers. The correlations between root biomass and site fertility characteristics seemed to be species specific. There was no correlation between soil acidity and root biomass. Beech fine root biomass decreased with stand age whereas pine root biomass increased with stand age. Fine root biomass at tree level correlated better than stand level root biomass with stand characteristics. The results showed that there exists a strong relationship between the fine root biomass and the above-ground biomass.

Comparison of Fine Root Dynamics in Scots Pine and Pedunculate Oak in Sandy Soil

In this study, we investigated the relationship between the seasonality of vegetation cover and that of fine root processes in a man-made forest in northern Belgium. Due to their contrasting foliar development, we expected different seasonal patterns of fine root growth and standing biomass between Pedunculate oak (Quercus robur L.), and Scots pine (Pinus sylvestris L.). Biomass and necromass of fine and small roots were estimated by repeated core sampling in February, April, June, August and October 2003. Measurements showed that Pedunculate oaks maintained more live fine roots in winter than Scots pines. However, Scots pines produced more than twice as much fine roots in spring, such that in summer both species had similar root mass. Scots pine root production started before-, but declined during leaf unfolding. Pedunculate oak roots, in contrast, started elongating only after bud break. For both species, fine root production peaked in JuneJuly, but was more than offset by drought-induced mortality at the end of July and early August. Summer drought in 2003 was exceptionally long and intense, significantly reducing leaf area, killing most new roots, and inhibiting root decomposition, such that the obtained results cannot be typical for this forest.

Fine roots and ectomycorrhizas as indicators of environmental change

Abstract Human-induced and natural stress factors can affect fine roots and ectomycorrhizas. Therefore they have potential utility as indicators of environmental change. We evaluated, through meta-analysis, the magnitude of the effects of acidic deposition, nitrogen deposition, increased ozone levels, elevated atmospheric carbon dioxide, and drought on fine roots and ectomycorrhizal (ECM) characteristics. Ectomycorrhizal colonization was an unsuitable parameter for environmental change, but fine root length and biomass could be useful. Acidic deposition had a significantly negative impact on fine roots, root length being more sensitive than root biomass. There were no significant effects of nitrogen deposition or elevated tropospheric ozone on the quantitative root parameters. Elevated CO2 had a significant positive effect. Drought had a significantly negative effect on fine root biomass. The negative effect of acidic deposition and the positive effect of elevated CO2 increased over time, indicating that effects were persistent contrary the other factors. The meta-analysis also showed that experimental conditions, including both laboratory and field experiments, were a major source of variation. In addition to quantitative changes, environmental changes affect the species composition of the ectomycorrhizal fungal community.

Biomass and production of fine roots in Japanese forests

To better understand the control of fine-root dynamics in Japanese forests, we reviewed studies conducted in Japan on fine-root biomass and production. Most of the data on fine-root biomass were obtained for conifer plantations in limited regions; the average fine-root biomass of dominant trees ranged from ∼50 g m−2 for Pinus species (n = 3) to ∼600 g m−2 for Cryptomeria japonica (n = 4) and Chamaecyparis obtusa (n = 3). These values are comparable with or less than those reported for other temperate forests mainly in North America or Europe. Information on fine-root production in Japanese forests remains limited. Fine-root production accounted for ∼30% of the net primary productivity in two deciduous forests, but similar data was not reported for coniferous forests in Japan. In Japanese forests, slope position is a key parameter controlling fine-root biomass that is greater on upper slopes than on lower slopes, probably because soil resource availability decreases upslope. Studies in manipulated soil environments (e.g., removing throughfall to simulate drought) also suggested that fine-root biomass and production were greatly affected by altered soil environments. Physiological control of fine-root dynamics was recently discussed via anatomical analyses of Chamaecyparis obtusa. Findings from Japanese studies generally support data on fine-root biomass and production obtained from other temperate regions. Further attempts to elucidate the influence of slope position (soil resource availability) on fine-root production would be useful to gain a more detailed understanding of the fine-root dynamics in Japanese forests.

Climate change increases the drought risk in Central European forests: What are the options for adaptation?

Abstract The paper presents information on the projected drought exposure of Central Europe, describes the anticipated dynamics of the regional forests, and identifies measures facilitating the adaptation of forests to climate change-induced drought risk. On the basis of an ensemble of climate change scenarios we expect substantial drying in southern Slovakia and Hungary, while such trends were found to be less pronounced for the Czech Republic and Austria. In response to these climate trajectories, a change in species composition towards a higher share of drought tolerant species as well as the use of drought resistant provenances are identified as paramount actions in forest adaptation in the region. Adaptation to aggravating climate change may need to use artificial regeneration to enrich local gene pools and increase the drought tolerance of stands. Increasing risks from pests, pathogens and other disturbances are expected as a result of more frequent and severe droughts, underlining the need to put a stronger focus on risk management principles rather than on indicators of productivity in silviculture and forest planning. A consolidation of disturbance monitoring systems and a broader use of pest dynamics and hazard rating models are paramount tools to facilitate this adaptation process in forest management. The effectiveness of all the suggested measures needs to be controlled by efficient forest monitoring systems, the consolidation of which seems to be a timely task. Systematic and long-term implementation of the presented measures should increase forest stability and resilience, and further secure the sustainable provision of ecosystem services under climate change. Abstrakt V článku sú prezentované informácie o očakávanom vývoji sucha v oblasti strednej Európy, je opísaná možná dynamika lesov v podmienkach zmeny klímy, a je vypracovaný systém opatrení umožňujúcich adaptáciu lesov na zmenu klímy. Na základe kolekcie scenárov zmeny klímy bol identifikovaný výrazný nárast intenzity sucha v oblastiach južného Slovenska a Maďarska, zatiaľ čo v oblasti Českej republiky a Rakúska bola zmena relatívne nevýrazná. S ohľadom na tento vývoj predstavuje úprava drevinového zloženia smerom k vyššiemu zastúpeniu sucho tolerujúcich drevín a širšiemu využívaniu proveniencií rezistentných voči suchu jedno zo základných adaptačných opatrení. V prípade výrazných zmien klímy narastá význam umelej obnovy, ktorá predstavuje nástroj na zlepšovanie druhovej a genetickej diverzity porastov a zvyšovanie ich tolerancie voči suchu. Narastajúci vplyv škodcov súvisiaci s rastúcim vplyvom sucha a ďalších abiotických činiteľov naznačuje potrebu orientovať pestovanie a hospodársku úpravu lesa viac na manažment rizík ako na maximalizáciu produkcie. Konsolidácia systémov monitoringu škodlivých činiteľov a širšie využívanie modelov dynamiky škodcov a hodnotenia rizík patria medzi ďalšie dôležité opatrenia podporujúce adaptáciu lesov na zmenu klímy. Všetky uvedené opatrenia musia byť podporené informáciami získanými na základe dlhodobého monitoringu lesa, ktorý však vyžaduje urýchlenú konsolidáciu. Systematická a dlhodobá realizácia prezentovaných opatrení podporí stabilitu a rezilienciu lesov a vytvorí predpoklady pre udržateľné poskytovanie ekosystémových služieb a funkcií v podmienkach zmeny klímy.

Effects of simulated drought stress on the fine roots of Japanese cedar (Cryptomeria japonica) in a plantation forest on the Kanto Plain, eastern Japan

Drought stress was simulated in a 28-year-old Japanese cedar plantation (Kanto Plain, Japan) between April and October 2004 by removing throughfall using rain shelters. Changes in fine-root parameters caused by this drought treatment were examined by sequential soil coring. Drought effects on fine roots were analyzed separately for particular soil depths (0–5, 5–15, and 15–25 cm) and root diameters (<1 and 1–2 mm). Generally, fine-root biomass and root tip numbers decreased by the drought treatment. Drought stress was most intense for fine roots in the topsoil and weakest for fine roots in the deepest soil layer. Fine roots less than 1 mm in diameter were affected more severely than 1- to 2-mm roots. The effect of drought treatment was most remarkable for the number of white root tips, which decreased to 17% of the control at the soil depth of 0–5 cm. These results suggest that white root tip is the most suitable indicator of drought stress. Simulated drought reduced production of fine roots less than 1 mm and 1–2 mm in diameter. Fine-root mortality was stimulated for roots less than 1 mm, but not for 1- to 2-mm roots. These results suggest that fine roots with larger diameters can survive drought stress at a level simulated in this study, but processes of fine-root production were inhibited regardless of the diameter classes. The duration of drought stress and phenology of fine roots should also be considered in diagnosing the effects of drought on fine-root parameters.

Individual biomass factors for beech, oak and pine in Slovakia: a comparative study in young naturally regenerated stands

Biomass conversion and expansion factors (BCEF) which convert tree stem volume to whole tree biomass and biomass allocation patterns in young trees were studied in order to estimate tree and stand biomass in naturally regenerated forests. European beech (Fagus sylvatica L.), Sessile oak (Quercus petraea (Mattuschka) Liebl.) and Scots pine (Pinus sylvestris L.) stands were compared. Seven forest stands of each species were chosen to cover their natural distribution in Slovakia. Species-specific BCEF are presented, generally showing a steep decrease in all species in the smallest trees, with the only exception in the case of branch BCEF in beech which grows with increasing tree size. The values of BCEF for all tree compartments stabilise in all species once trees reach about 60–70-mm diameter at base. As they grow larger, all species increase their allocation to stem and branches, while decreasing the relative growth of roots and foliage. There are, however, clear differences between species and also between broadleaves and conifers in biomass allocation. This research shows that species-specific coefficients must be used if we are to reduce uncertainties in estimates of carbon stock changes by afforestation and reforestation activities.

Post-disaster Forest Management and Bark Beetle Outbreak in Tatra National Park, Slovakia

Abstract In November 2004, the Alžbeta windstorm hit the mountainous areas of northern and central Slovakia. The most affected area was Tatra National Park, where downslope wind damaged 12,000 ha of forest, mostly Norway spruce (Picea abies [L.] Karst.). In the areas with the highest level of nature conservation, about 165,000 m3 of damaged wood was left uncleared. These uncleared sites triggered a serious bark beetle outbreak, where Ips typographus (L.) was among the dominant species. The aim of our work was to quantify and map forest damage resulting from this windstorm and subsequent insect outbreak in Tatra National Park. The objective of this article is also to present simple geographic information system (GIS) techniques available to forest managers for the detection and mapping of bark beetle infestations. The infested areas were studied using GIS and a series of color-infrared aerial photographs taken in 2005–2009. More than 50% of all damage was recorded within 300 m, and more than 75% within 500 m, of uncleared windthrow sites. Based on our findings, we propose reinforcing post-disaster monitoring with an emphasis on (1) data acquisition and processing and (2) management of I. typographus outbreaks. For instance, we recommend using 300-m phytosanitary buffer zones in mountain spruce forests to prevent substantial beetle invasion from uncleared windthrow into adjacent stands.

THE RESEARCH SITE VRCHSLATINA - AN EXPERIMENTAL DESIGN AND THE MAIN AIMS

Abstract The research site “Vrchslatina” was established in the spring of 2009 with the aim of studying production processes and the structure of net primary productivity in young forest stands. The beech and spruce stands grown at the site were selected because they originated from natural regeneration and are nearly of the same age. In 2009, we established 5 research plots in each stand with the aim of measuring basic tree characteristics. Moreover, we excavated entire trees to construct allometric relations for the specific tree compartments. In the consecutive years (2010, 2011 and 2012), we also included grass communities dominated by Calamagrostis epigejos in our studies. Besides studying production processes of all tree compartments (i.e. for trees: foliages, branches, stem, coarse and fine roots, for grasses and herbs: below- and above-ground parts), we monitored several atmospheric characteristics, followed by soil characteristics and eventually added a measurement of soil respiration. The results indicated that forest stands (even though they were in their initial growth stages) sequestrated much more carbon than the grass communities. Moreover, we proved the considerable influence of climatic conditions (especially the sum of precipitation) in the particular years for net primary productivity.

Biomass of fine and small roots in two Japanese black pine stands of different ages

The biomass and the spatial distribution of fine and small roots were studied in two Japanese black pine (Pinus thunbergii Parl.) stands growing on a sandy soil. More biomass of fine and small roots was found in the 17-year-old than in the 40-year-old stand. There were 62 g m−2 of fine roots and 56 g m−2 of small roots in the older stand, which represented mean values of 608 g for fine and 552 g for small roots per tree, respectively. In the younger stand, a total of 85 g m−2 of fine roots and 66 g m−2 of small roots were determined, representing a mean of 238 g for fine and 186 g for small roots per tree, respectively. Fine and small root biomasses decreased linearly with a soil depth of 0–50 cm in the older stand. In the younger stand, the fine and small roots developed only up to a depth of 30 cm. Horizontal distributions (with regard to distance from a tree) of both root groups were homogeneous. A positive correlation in the amount of biomass of fine and small roots per m2 relative to tree size was found. Fine and small root biomasses increased consistently from April to July in both stands. The results also indicated earlier growth activity of the fine roots than small roots at the beginning of the growing season. The seasonal increases in fine and small root biomasses were slightly higher in the younger stand than the older stand.