Soil total phosphorus and nitrogen explain vegetation community composition in a northern forest ecosystem near a phosphate massif

The relationship of the community composition of forest vegetation and soil nutrients were studied near the Sokli phosphate ore deposit in northern Finland. Simultaneously, the effects of the dominant species and the age of trees, rock parent material and soil layer on these nutrients were examined. For this purpose, 16 study plots were established at different distances from the phosphate ore along four transects. Phosphate mining may take place in Sokli in the future, and the vegetation surveys and soil sampling conducted at the plots can be used as a baseline status for following the possible changes that the mining may cause in the surrounding ecosystem. The total phosphorus (P) and nitrogen (N) contents of the soil humus layer were positively related with species number and abundance of the understorey vegetation, and the correlation was slightly higher with P than N. This is interesting, as N usually has the most important growth-limiting role in boreal ecosystems. The spatial variation in the content of soil elements was high both between and within plots, emphasizing the heterogeneity of the soil. Dominant tree species and the soil layer were the most important environmental variables affecting soil nutrient content. High contents of P in the humus layer (maximum 2.60 g kg(-1)) were measured from the birch-dominated plots. As the P contents of birch leaves and leaf litter were also rather high (2.58 and 1.28 g kg(-1), respectively), this may imply that the leaf litter of birch forms an important source of P for the soil. The possible mining effects, together with climate change, can have an influence on the release of nutrients to plants, which may lead to alterations in the vegetation community composition in the study region.Peer reviewe

Forest mosses sensitively indicate nitrogen deposition in boreal background areas

Mosses take up nitrogen (N) mainly from precipitation through their surfaces, which makes them competent bioindicators of N deposition. We found positive relationships between the total N concentration (mossN%) of common terrestrial moss species (feather mosses Pleurozium schreberi and Hylocomium splendens, and a group of Dicranum species) and different forms of N deposition in 11-16 coniferous forests with low N deposition load in Finland. The mosses were collected either inside (Dicranum group) or both inside and outside (feather mosses) the forests. Deposition was monitored in situ as bulk deposition (BD) and stand throughfall (TF) and detected for ammonium (NH4+-N), nitrate (NO3--N), dissolved organic N (DON), and total N (N-tot, kg ha(-1)yr(-1)). N-tot deposition was lower in TF than BD indicating that tree canopies absorbed N from deposition in N limited boreal stands. However, mossN % was higher inside than outside the forests. In regression equations, inorganic N in BD predicted best the mossN% in openings, while DON in TF explained most variation of mossN% in forests. An asymptotic form of mossN% vs. TF N-tot curves in forests and free NH4+-N accumulation in tissues in the southern plots suggested mosses were near the N saturation state already at the N-tot deposition level of 3-5 kg ha(-1) yr(-1). N leachate from ground litterfall apparently also contributed the N supply of mosses. Our study yielded new information on the sensitivity of boreal mosses to low N deposition and their response to different N forms in canopy TF entering moss layer. The equations predicting the N-tot deposition with mossN% showed a good fit both in forest sites and openings, especially in case of P. schreberi. However, the open site mossN% is a preferable predictor of N deposition in monitoring studies to minimize the effect of tree canopies and N leachate from litterfall on the estimates. (C) 2020 Elsevier Ltd. All rights reserved.Peer reviewe

Metsänhoidolla parempia mustikka- ja puolukkasatoja

Metsien ei-puuaineisia tuotteita, kuten marjoja, arvostetaan yhä enemmän muun muassa niiden terveysvaikutusten vuoksi. Vaikka ulkomaiset poimijat ovatkin kasvattaneet marjojen kaupallista poimintaa ja satojen talteenottoa, valtaosa marjasaaliista päätyy edelleen suomalaisten kotitarvekäyttöön. Myös metsänomistajat ovat entistä monitavoitteisempia. Metsäsuunnittelussa on pystyttävä arvioimaan, miten eri metsänkäsittelytavat vaikuttavat puuntuotantoon ja marjasatoihin

Veden imetyksen vaikutukset metsämaahan ja kasvillisuuteen sekä vajo- ja pohjaveden laatuun. VIVA-tutkimushankkeen loppuraportti.

Myynti ja tilaukset: Hämeenlinnan kaupungin vesilaitos, Suosaarentie 4, 13210 Hämeenlinna Puh. 03-621 2290, Fax 03-621 2758

Response of ground macrolichens to site factors, co‐existing plants and forestry in boreal forests

Aim Ground lichens have declined in boreal and temperate Europe. The potential causes of the decline were explored by analysing the response of lichen cover to forest management, site and stand variables as well as co-existing plants in different boreal vegetation subzones. Location Finland. Methods Understorey vegetation was surveyed on a systematic network of 1721 sample plots in forests on mineral soil. The response of macrolichen cover to explanatory variables was analysed by generalised linear mixed models (GLMMs). Results Ground lichens favoured old Pinus sylvestris forests on xeric sites with sufficient light conditions. Intensive forest management regimes, such as regeneration cutting and soil ploughing decreased lichen cover, while lighter scarification methods had less effect on lichens. Lichens benefitted from intermediate cutting on sites with low bryophyte cover. Lichens responded similarly to site and stand variables in all boreal subzones, showing that despite heavy reindeer grazing these response patterns apply also in the northern boreal subzone. Lichens showed both negative (Vaccinium myrtillus, Empetrum nigrum and Calluna vulgaris) and positive (Vaccinium vitis-idaea) responses to increasing dwarf shrub cover. Generally, lichens negatively responded to increasing bryophyte cover, indicating either that bryophytes benefit from a decline of lichens or that there is real competition between these groups. The negative relationship between bryophytes and lichens strengthened as the tree canopy becomes denser. Conclusions Our study provides new quantitative insights into the effects of forest management and changes in forest structure as underlying factors for lichen decline both inside and outside the reindeer-herding area (i.e., the northern boreal subzone). These factors include increased canopy cover with increased shading as well as disturbance caused by regeneration cutting and soil preparation. The possible effects of the long-term legacy of nitrogen deposition, lack of forest fires and climate change are also discussed

Veden imeytyksen vaikutukset metsämaahan ja kasvillisuuteen - VIVA. Tutkimushankkeen väliraportti 15.12.1996

monist

Veden imeytyksen vaikutukset metsämaahan ja kasvillisuuteen - VIVA. Tutkimushankkeen väliraportti 15.12.1997

monist

Fine root longevity and carbon input into soil from below- and above ground litter in climatically contrasting forests

The major part of carbon (C) flow into forest soil consists of continually renewed fine roots and aboveground litterfall. We studied the belowground C input from the fine root litter of trees and understorey vegetation in relation to their aboveground litterfall in two Norway spruce (Picea abies L.) stands located in northern and southern Finland. The production of fine roots was estimated by using turnover and biomass data from minirhizotrons and soil cores. The foliage litter production of trees was estimated from litter traps, and that of the understorey vegetation from its annual growth and coverage. Finally, we augmented the data with four spruce plots in Sweden in order to study the above- and belowground litter ratios along latitudinal and soil fertility gradients. The fine root biomass of spruce trees per stand basal area was almost double in the northern site compared to the southern site. Furthermore, spruce fine roots in the north persisted significantly longer (97 ± 2 weeks) than spruce roots in the south (89 ± 2 weeks) or understorey fine roots at both sites. The annual production of tree foliage litter was higher in the southern stand, but the total amount of litter (including trees and understorey, above- and belowground) was similar at both sites, as was the ratio between the above- and belowground litter production. The role of understorey vegetation was greater in the northern site where it was responsible for 23% and 33% of below- and aboveground litter production, respectively, compared to 11% and 15% in the south. Thus, both below- and aboveground understorey C input is substantial and should be taken into account in ecosystem C cycle models. The regression between the aboveground:belowground litter production-ratio and the C:N-ratio of the organic layer (combined data from Finland and Sweden), showed that the share of belowground litter production increased when site fertility decreased. This shift in the litter production pattern from above- to belowground in the least fertile sites may have an impact on litter C quality and soil C storage