Expertise
2025: Poor starting conditions for forests
Marco Natkhin, Tanja Sanders | 02.06.2025
Forests are affected by an unusually dry spring: On our research site “Britz”, only a quarter of the usual precipitation since March. The result: poor growing conditions and hardly any groundwater recharge.
This year, it only rained 35 millimetres at the forest hydrology test site in Britz since the beginning of March to the end of May. This is a quarter of the mean precipitation sum compared to the same months in the years 1993 to 2022. In January, precipitation was still above average but then levelled off. In total it only rained 140 millimetres this year. This is the second-lowest value since 1993. Only 2003 (139 millimetres) were drier in the same period from January to May.
In contrast to the wet winter half 2023/2024, the starting conditions for forest vegetation are, thus, poor this year. The landscape water balance is also suffering as little or no new groundwater is formed due to the drought and vegetation is depleting the soil water reserves.
Last year, the researchers were able to measure a comparatively large amount of deep percolating water below the pine trees in their test areas. The 38 millimetres measured even exceeded the total amount of the previous ten years. This year, due to the extreme drought, it is unlikely that deep percolating water will be measurable beneath the pines.
Monthly precipitation amounts in mm for the years 2023-2025 and long-term average
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Okt | Nov | Dez | Year | |
Average 1993-2022 | 53 | 42 | 42 | 31 | 57 | 68 | 76 | 59 | 52 | 45 | 45 | 51 | 619 |
Year 2023 | 81 | 50 | 100 | 49 | 12 | 53 | 42 | 58 | 12 | 82 | 54 | 103 | 696 |
Year 2024 | 64 | 90 | 31 | 35 | 29 | 48 | 60 | 57 | 35 | 39 | 57 | 42 | 588 |
Year 2025 | 74 | 32 | 11 | 10 | 14 | 140 |
Currently, the drought stress on the intensive monitoring area in Britz is still limited. So far, damage was mainly caused by night frost at the beginning of May, after leaves had already unfolded on oaks and beeches. Frost damage particularly affects young stands that are not under a protective old stand.
