Current state
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The mean growing-stock volume of the French forests is estimated at 2.8 billion cubic meters. [1]
This volume calculated by the French National Forest Inventory (NFI) represents the stem volume of live trees with a diameter at breast height greater than 7.5 cm, from the stump to a minimum top diameter of 7 cm over bark.
The growing-stock volume per hectare is 172 m³. |
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| Definition of the growing stock. |
For more information, see the article "More than 190 tree species inventoried in France"
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Broadleaves (hardwoods) account for almost 2/3 of the growing stock, which represents 1.8 billion m3. Oaks (including pedunculate, sessile, pubescent and evergreen oaks) make up more than a quarter (29%) of the total growing-stock and 44% of the hardwoods’ growing stock. Beech accounts for 10% of the total growing stock. Conifers (softwoods) account for almost 1 billion cubic meter. Norway spruce accounts for 6% of the growing stock and silver fir for 8%. Together, Norway spruce and silver fir represent 40% of the softwoods in terms of growing stock. |
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For broadleaves, trees with a diameter below 37.5 cm account for more than 50% of the growing stock volume. For conifers, 80% of the volume is composed of trees with diameters between 17.5 and 57.5 cm.
Growing-stock volume, depending on diameter classes and leaf type [2]. |
Evolution of the growing stock
Over the past 4 decades, a significant increase in growing stock has been observed, rising from 1.8 billion m3 in 1985 [3] to 2.8 billion m3 today, which represents a 50% increase.
This increase amounts to almost 1 billion m3, which corresponds to the current growing stock in the Grand Est, Bourgogne-Franche-Comté and Centre-Val de Loire regions combined.
During this period, the growing stock per hectare increased from 137 m3/ha to 172 m3/ha. Meanwhile, the number of trees per hectare slightly decreased. Stands are producing more because of larger and/or taller trees.
The increase in growing stock is higher for hardwoods (+65%, +720 Mm3) compared to softwoods (+38%, +270 Mm3).
Evolution of the growing stock of living trees between 1985 and 2023. |
Deadwood
In addition to measurements from live trees, data are also collected from standing and fallen deadwood. In 2023, the volume of standing deadwood represents 148 million m3, or 5% of the volume of all (live and dead) standing trees. Fallen deadwood accounts for 289 million m3. On average, one hectare of forest area contains 9 m3 of standing deadwood and 18 m3 of fallen deadwood.
