Seventy-year history of management using low-intensity harvesting methods: weak impact on biodiversity of hemiboreal Scots pine forests

Abstract

Less intensive harvesting methods (e.g. selection cutting, shelterwood cuttings) are recommended as alternatives to clearcutting for maintaining mature forest biodiversity in the process of forest regeneration. However, the long-term impact of low-intensity harvesting methods have rarely been studied. Our aim was to clarify the long-term effects of repeated selective cutting, thinning and shelterwood cutting on the richness, abundance and species composition of vascular plants, bryophytes and lichens in Scots pine forests. Data were collected from 25 mature stands located in dry Podzols in south-western Estonia with a known management history for the last 70 years. Altogether 35 vascular plant, 41 bryophyte and 78 lichen species were recorded, including five species with conservational value. Generally, the management history was not related to species richness, except a negative correlation with the species number of epiphytic lichens on conifer trees. In addition, the abundance of two lichen species from the genus Chaenotheca was lower in more frequently managed stands. Species richness and composition were most strongly affected by soil pH and light conditions. We conclude that long-term low-intensity harvesting of Scots pine forests on nutrient poor Podzols maintains suitable habitats for vascular plants, bryophytes and lichens, confirming its suitability for sustainable forest regeneration.

Forest fires have long-term effects on the composition of vascular plants and bryophytes in Scots pine forests of hemiboreal Estonia

“…In general the soil pH of the studied sites was very low, ranging from 2.1 to 3.3, therefore the higher richness of several plant groups on sites with higher pH can be expected and it is in accordance with several former studies (Pausas 1994;Olden et al 2016). The richness of bryophytes (both mosses and liverworts as well as epixylic bryophytes) was higher in sites with higher soil nutrient content (PC2) that is also in accordance with expectations for plant communities on nutrient poor soils, similar to outcomes from a study of vegetation patterns in nutrient poor pine forests managed with low-intensity harvesting methods in south-western Estonia (Tullus et al 2020).…”

“…Although the long-term effects of forest fires and logging on understorey vegetation are often believed to be similar, it has not been wisely tested especially in the forests of Northern Europe (but see Paquette et al 2016;Rowe et al 2017;Jean et al 2019 for comparisons to forests of North America). When results of our fire chronosequence were compared with the results of a study in dry boreal Scots pine forests managed with low-intensity methods (Tullus et al 2020), the species richness of bryophytes was similar in both fire-origin and logged stands (average richness of bryophytes 10.9 and 10.8, respectively). At the same time the richness of vascular plants was slightly higher in logged stands, being on average 10.6 for logged stands and 7.8 for fire-origin stands.…”

“…The sides of the vegetation plot were positioned parallel to cardinal directions. In every vegetation plot the lists of vascular plant and bryophyte species found were compiled following a similar methodology as described in Tullus et al (2020). The cover of every species was evaluated visually following a 5-degree cover-abundance scale (1 = cover 1-5%, 2 = cover 6-20%, 3 = cover 21-50%, 4 = cover 51-75%, 5 = cover 76-100%; 0.5 was used for species covering less than 1%).…”

The biodiversity of birch stands in agricultural landscapes of Estonia is associated with past land use, restoration approach, site and landscape variables

“…The direct effects of restoration approach, past land use, site and landscape variables on the richness of vascular plants, bryophytes and lichens in birch stands depended on the taxonomic and ecological groups of species. The richness of shrubs was positively correlated with soil pH, coinciding with the results from pine forests in the same region (Tullus et al, 2020). At the same time, the number of shrubs was lower in plantations in comparison with the other two stand types for the reasons discussed above.…”