Ancient trees critical to forest ecosystems

A study in the field of theoretical evolutionary ecology published in Nature plants shows the importance of ancient trees for the genetic diversity of forest ecosystems and thus their adaptive capacity to, for example, climate change. Your contribution to protecting more old-growth forest is crucial for the future.

Using empirical data as a starting point, the researchers studied the occurrence of ancient trees using a stochastic model, which concludes that up to 1% of a population of trees with a mortality rate of 1.5% may reach an age at which they can be considered ancient. Which trees and how many are determined by many different factors, but one prominent factor is population size. The more trees and the larger the area left untouched, the greater the chance that a few trees can become ancient.

The bottom line is that ancient and even old and mature trees (which together make up up to 25% of old-growth forest individuals) play a crucial role in the evolutionary adaptive capacity of forest ecosystems by contributing genetic material that has been best adapted to all the different conditions that have prevailed over the past 500+ years. As conditions change, old-growth forests with their high genetic diversity have a much better chance of adapting to new conditions than young even-aged spruce monocultures with minimal genetic diversity.

In addition to protecting the ancient and old trees, it is the size of the population that determines the likelihood of new ancient trees emerging in the long term. Thus, it is not enough to protect individual trees, but larger areas of old-growth forest must be protected to enable forest ecosystems to cope with current and future climate change.

It's not just trees that become ancient. Fungi that form mycorrhizae with tree roots also develop genetically ancient populations that are adapted to meet many different ecological conditions under varying climates. A Swedish research project has studied how the proportion of trees left behind at deforestation affects the mycorrhizal community.

When old-growth forests are cleared and replaced by spruce monocultures, not only does the ecology of the tree layer change, but old-growth ground fungi almost disappear and other nutrient-demanding fungi migrate in, which can cause a fast-growing 40-50 year-old spruce plantation to leak carbon into the atmosphere instead of storing it in the forest. Such plantations thus contribute to the climate crisis rather than slowing it down.

When the oceans passed the point of no return in 2014 in terms of extreme heat for at least 50% of the months of the year in the surface waters of all the world's oceans, the Earth's climate catastrophe became a fact. As ocean ecosystems collapse, old-growth forest ecosystems, with their adaptive capacity, are the most important remaining natural carbon sinks on the planet. To deforest a single old-growth forest is to contribute to increased climate catastrophe and thus species extinction and loss of human life.

Do your bit, contribute to Naturarvet so that more old-growth forest can be protected quickly for present and future generations.

The study on ancient trees can be read here:
https://www.nature.com/articles/s41477-021-01088-5

Swedish research on how logging negatively affects vital mycorrhizal fungi:
https://besjournals.onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2664.13363
English summary:
https://www.slu.se/ew-nyheter/2019/4/sparade-trad-vid-avverkning-skyddar-mykorrhizasamhallet/

On the secret life of fungi:
https://www.sverigesnatur.org/natur/svamparnas-hemliga-liv/

You can read about the extreme heat of the oceans here:
https://www.theguardian.com/environment/2022/feb/01/extreme-heat-oceans-passed-point-of-no-return-high-temperatures-wildlife-seas

Naturarvet