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LVM is Investigating the Spread of the Groundcedar

There are two species of groundcedar to be found in Latvia: the more common greenish-coloured creeping jenny (Diphasiastrum complanatum) and the less common blue-grey blue clubmoss (Diphasiastrum tristachyum), which is slightly smaller than the creeping jenny. In LVM Vidusdaugava Region, especially in the Lāčplēša and Taurkalne forest massif, the creeping jenny is quite common.

Aigars Luste, LVM Vidusdaugava Region Senior Planner, in 2016, when preparing for forest thinning, identified and noted the actual forest boundaries in the forest, surveyed the wood stock to make a decision on the most appropriate tending model in the forest stand, and found the groundcedar in an area of about 3 hectares. Further felling site works were discontinued, and the planner informed LVM Environmental Expert Vija Kreile about his finding.

According to the site survey, Environmental Expert Vija Kreile observed that the area of the deposit of the creeping jenny covers at least 10 ha. Forest management activities have been carried out throughout the area between 2004 and 2011: tending of young stands, thinning, pruning of growing trees and sanitary selective felling. These operations were carried out without any special instructions, since there was no protected plant present in the area.

“The creeping jenny grew in vital in places where it was provided with suitable growing conditions - scattered lighting, exposed soil areas and less competition from other ground vegetation species. A higher density of the groundcedar was recorded in the areas where thinning had been performed in 2009, and the plants were more likely to spread through the timber delivery paths and openings,” says Vija Kreile, LVM Environmental Expert.

With a view of studying the impact of forestry activities on the distribution and further development of the protected plant, Vija together with LVM Environmental Planning Specialist Guna Baltiņa decided to permit felling in an area of 3.7 hectares, with the introduction of plots for monitoring - repeated observations.

In 2016, plots with an area of 4 square metres each were arranged in a row: 28 plots where it was planned to carry out pine thinning, and 27 plots in the rest of the area where economic activity has previously occurred but is currently not planned. Measurements were made on all plots using the Braun-Blanquet method to determine the number of trees, bushes and shrubs (heather, blueberry and cowberry), total moss, lichen projecting cover, and areas occupied by stumps, forest litter and bare earth. In the autumn of 2018, after the thinning carried out in 2017, repeated measurements were made.

“No significant changes in groundcedar habitat have been found, as a relatively short time has elapsed. Major conclusions will be made after the next measurements within the framework of the monitoring in 2020. However, it can be seen that the spread and vitality of the plant has not diminished, on the contrary - the occupied area has grown by about 3% compared to the first measurements,” says Vija Kreile, LVM Environmental Expert.

Similar conclusions regarding the relation of the creeping jenny and the economic activity in LVM North Kurzeme Region Zilokalnu Forest District according to the monitoring data were also made by LVM Senior Environmental Expert Ilze Rēriha, namely,s a vital creeping jenny deposit in an area of 5.3 ha is located in a forest affected by the economic activity, whereas in the surrounding untouched forests there are no deposits of this plant at all.

The development of the creeping jenny from spores occurs very slowly, but adult plants spread well vegetatively along forest roads, forest clearances and mineralized bands.

“In the area where there is no regular economic activity, the presence of common heather increases, and it suppresses groundcedar stands. In turn, in places where it was not restricted, there are favourable conditions for the spread of the creeping jenny. Therefore, we plan to continue to manage it in the future, taking care of the conservation of the species and the creation of appropriate growth conditions. It is reasonable to assume that other light-demanding protected plants, such as fastigiate gypsophila, sand pink and pulsatilla patens, also require ground cover interruptions to provide favourable conditions for growth. Alongside, in the band where the overgrowth along the forest road is regularly removed, a new pulsatilla patens deposit has been found,” says LVM Environmental Expert.

In the areas managed by LVM, there are 36 field deposits with the total area occupied by the plant accounting for 34 hectares: in Vidusdaugava there are 20 deposits – 18 hectares, in South Latgale there are 6 deposits - 9 hectares, and in North Kurzeme 6 deposits - 6.5 hectares, and elsewhere. There are also 135 point-type deposits: in South Latgale - 31, East Vidzeme, Vidusdaugava, North Kurzeme - 23 to 26 deposits.

The creeping jenny grows in acidic soils, in dry coniferous, mainly pine forests. Other species, such as spruce and herbaceous plants, which obscure the sun, and heather, cause competition not only for light but also for nutrients in the soil.

The plant is found not only in specially designed micro-reserves and 18 micro-reserves for forest habitats, but also outside them - especially in large pine forests across the country, more often in the central and eastern parts. The creeping jenny is displayed on LVM GEO maps as points, if individual plants or groups of plants of a few square metres are found, or as squares - if deposits form large stands.