Abstract
The present study demonstrates the importance of biomass as a renewable energy source; the forest ecosystems with high-energy potential have a high carbon storage capacity and the key factor being the amount of biomass stored.
The study area was Romania, located in Europe, where the author selected 90 forest ecosystems spread along an altitudinal gradient from the lower Danube floodplain (15 m asl.) to the Carpathian Mountains (2100 m asl.).
In each ecosystem type, five circular areas of 500 m2 were selected, where the following parameters were measured and estimated: tree species composition, average age, total timber volume (m3/ha) and annual productivity (m3/ha/year), and wood density (g/cm3). The calorific capacity of the wood was determined by calorimetric methods using the Bomb Calorimeter (Model-IKA C2000), the carbon content was measured with a CE InstrumentsEA-1110 CHNS-O dispositive, and the carbon stock was calculated using CO2FIX31EXE based on woody biomass carbon stocks.
From the point of view of standing crop biomass, the most valuable are pure forests, 130-year-old (355 t/ha); mixed beech forests where beech dominates, 110-year-old (300.8 t/ha); and the planted forest, the 35-year-old poplar plantation was the most productive (199.5 t/ha). The highest productivity was in the 10-year-old planted poplar forest (7.14 t/ha/year), followed by the 110-year-old sessile oak forest (2.35 t/ha/year), and 110-year-old mixed beech forests, where 50% beech in composition. In natural forests, in terms of energy, the most efficient are pure beech forests and those mixed with fir and spruce, and for the planted forest, it is the poplar forest.
A direct correlation is between the capacity to produce and store energy of the forest ecosystems and the capacity to fix and store the carbon through photosynthesis, and the biomass is a key factor that proves this.