Biomass dynamics of mature and old-growth forests in Central Europe: proforestation as a tool to mitigate climate change

Abstract

Climate change is nowadays major challenge to ecosystems on Earth. Forest as one of the biggest ecosystems is hugely affected by those challenges. Many professionals in forestry department suggest that simply reforest areas after timbering or any kind disturbances will be enough to fight against those challenges. This research will be providing data to show that alternative approach to management in forest through „proforestation“ can be easier, possibly also cheaper way how to accumulate biomass in the forest which binds carbon dioxide and thus helps to mitigate climate change. It will also show impact on mortality rates in forest after applying this approach in forest.

Methodology

The project’s fieldwork will take place in the Jizera Mountains and wooded regions of Slovakia and Romania that are a part of the REMOTE Primary Forests initiative. A portion of the information that will be used for research purposes will come from databases of information that has already been gathered and information that will be gathered throughout the time period outlined in the study timeline below. The recommended months for fieldwork in 2023 are August, September, and October. In 2024 time of the field work have yet not been determined.

To be more specific, data which were collected in previous measurements and will be again collected for re — measurements of plots during fieldworks will mainly contain plot data (id, location, forest type data); tree level data (id, species, DBH, height, crown diameter, status, growth pattern, layer, in the case of dead wood decay class, decay height) and chronological data (core bore) necessary for purposes of the project. From previous measurements we already have chronological data and amount of biomass processed. Same data will need to be gained from collection in 2023.

We will follow the REMOTE Primary Forest project’s methods for data collection. Areas with a minimum size of 1500 m2 and a maximum radius of 21,85 m will be established in order to collect data for our research. For every tree we will determine what species of each tree it is, its DBH at 1,3 m (only for tree bigger than 6 cm in diameter), height, and, in the case of living trees, the location and radius of the crown, will all be identified. Then we will collect tree cores using tree borers. In the inner radius (200 m2) we will collect core boreholes from trees with diameter over 6cm. In the middle area (1000 m2) from tree with diameter over 20 cm and in outer area (1500 m2) from trees with diameter over 60 cm.

In the case of dead wood, we will include two types of wood: standing dead wood and downed dead wood found on the forest floor. Using the line intersect approach, coarse woody debris will be measured in each plot, the DBH and height of dead standing trees w measured, and the decay stage in each case.

After collection of dendrochronological data, they will be processed with microscope and LinTap measurement table with computer programmes TSAPWin and Cdendro.

As the first step in statistical part of research we will use allometric equations for live trees by Forrester and others (2017) for biomass calculations. These equations use DBH (cm) and basal area (m2 ha-1) as the predictor variables. For estimating volume of standing dead wood we will measure DBH and height and the use appropriate package in R. For downed deadwood we will use formula: where V is volume of the wood, d is deadwood diameter and L is length of the sample (Van Wagner, 1968). To see possible differences in biomass accumulation in the area we will use Kolmogorov — Smirnov test to see differences in biomass accumulation between each plot comparing to total amount of biomass in the area. To estimate mortality in the area we will use data from previous measurements and re — measurements.

We will employ equations by Meyer and others (2021) that characterize density-dependent and density-independent mortality to determine mortality rates in plots. These equations will take into account the pressure of competition as well as an unrelated effect that may have a significant impact on biomass accumulation.

Research objectives

The research objective is to examine how the biomass changes over time in old-growth forests that have not been managed. The study will attempt to provide insight into the general questions of how old-growth and mature forests absorb carbon and what long-term patterns exist in the dynamics of biomass by analysing changes in biomass over time in the study forests using permanent plots with repeater measurements and tree ring data. In particular we want to know.

1) The examined mature and old-growth forests are gaining biomass or losing biomass?

2) How is the biomass build-up in the forests under study affected by the demographic processes in the forests, such as competition, mortality, and natural disturbances?

Literature

Forrester DI, Tachauer IH, Annighoefer P, Barbeito I, Pretzsch H, Ruiz-Peinado R, Stark H, Vacchiano G, Zlatanov T, Chakraborty T, Saha S. (2017). Generalized biomass and leaf area allometric equations for Europeantree species incorporating stand structure, tree age and climate. Forest Ecology and Management. 396:160–75.

Van Wagner, CE. (1968). The line intersect in forest fuel sampling. Forest science. 14 (1): 20–6.

Meyer, P., Nagel, R., Feldmann, E. (2021). Limited sink but large storage: Biomass dynamics in naturally developing beech (Fagus sylvatica) and oak (Quercus robur, Quercus petraea) forests of north — western Germany