Tree biomass and deadwood density into aged holm oak (Sardinia) and beech coppices (Tuscany)

Abstract

Tree biomass and deadwood density into aged holm oak (Sardinia) and beech coppices (Tuscany). Current National Forest Inventory highlight the further increase over the last two decades of coppice area under the position of mature standing crop or in the post-cultivation phase, both being developed throughout the original cultivation area. This pattern, mainly due to the unprofitable fuel wood harvesting, also involved holm oak and beech forests, some of the most diffused forest covers in Sardinia, along the Apennines and pre --Alps. The alternative management option to ageing (the pro-active way of coppice conversion into high forest) has been also practiced in the public domain, but on much smaller areas as compared with those undergoing post-cultivation phase. Aged coppices located into medium-good site classes showed a positive growth pattern resulting in a high, age-related, wood matter storage. At the meantime, regular mortality occurring since former rotation into the fully-stocked shoot populations, stocked up high deadwood amounts, this becoming an outstanding attribute of these types. Carbon storage is becoming one of the major tasks attributable to these systems within the post-cultivation phase. Purposes are here to: (i) estimate living woody and standing + lying deadwood mass densities; (ii) determine deadwood/living mass ratio; (iii) verify lying deadwood decay class; (iv) analyse diversity between two sites aged likewise but different as for geographical location and tree species. A holm oak coppice aged 55 in Sardinia and a beech coppice aged 57 in Tuscany were selected at the purpose. Both stands have been developing the post-cultivation phase since two-three times the traditional rotation and represent the maximum ages in this position. Living and standing dead woody dry mass density were determined in each site by specific allometric functions. Lying deadwood amount was assessed by a sampling design covering systematically the full test area. Three decay classes were determined according to Hunter (modified). The tree species, both shade-tolerant, showed a similar pattern as for time of wood formation and its transfer to deadwood, as well. The main difference consists only in their evergreen and deciduous habit. Auto-ecology seems to be the main driver of stand development as for carrying capacity, mortality rate and survival time into the overstocked stand structures. Leaf standing mass and leaf /thin branches ratio are two and three times higher in holm oak, consistently with its biology. Living woody mass density is made basically by stem and thick branches (88%) and varies from 322 Mg ha i.e., from 9 to 11% of living woody mass. Standing deadwood is 70 to 73% of total amount. As for lying material, the intermediate decay class is prevailing: 74%, (beech) and 66% (holm oak). Both dynamics and age-related data suggest the active role these types may play in soil conservation, improvement of forest quality and carbon storage. The need of a consistent monitoring of the further post-c...

Structure and Dynamics of Deadwood in Pine and Oak Stands and their Role in CO2 Sequestration in Lowland Forests of Central Italy

“…In this Mediterranean area, the possibility of a continuous accumulation of deadwood over time is usually a result of the natural disturbance and the abandonment of the timber harvest [7,[46][47][48][49][50][51] or, better, of the choice to carry out minimal interventions since the removal of deadwood has been one of the most frequent operations in forest, favoured by the rights of use of local populations for the collection of deadwood as firewood [15,24,25] and the fear of forest fires by managers. Deadwood is mainly caused by tree mortality and the accumulation is due to the production coupled with the degradation and decay of biological agents [6,[52][53][54].…”

“…The diameter distribution of the snags combined with the decay stage provided further information. The aging of coppice led to the death of smaller and less competitive trees [7,46,47]. The decay stage, DC 1, indicated recent death.…”

“…RDT progressively increase as time elapses from management abandonment. Downed deadwood turns prevalent in other mesic oak stands [47,51,52].…”

C and N concentrations in different compartments of outgrown oak coppice forests under different site conditions in Central Italy

“…Typical physiognomy of a mature coppice forest is in fact a young, densely stocked crop. In former rotations acted-as a rule-at this stage, woody mass was harvested before the full occurrence of heavy competition and (Bertini et al 2012), then to stand age and site quality; thus, the more fertile sites usually accelerating the progress of tree death and decay rates as well.…”