Aim of the study. To estimate biomass and carbon accumulation in a young and disturbed forest (re... more Aim of the study. To estimate biomass and carbon accumulation in a young and disturbed forest (regenerated after a tornado) and an aged cork oak forest (undisturbed forest) as well as its distribution among the different pools (tree, litter and soil). Area of study. The north west of Tunisia Material and methods. Carbon stocks were evaluated in the above and belowground cork oak trees, the litter and the 150 cm of the soil. Tree biomass was estimated in both young and aged forests using allometric biomass equations developed for wood stem, cork stem, wood branch, cork branch, leaves, roots and total tree biomass based on combinations of diameter at breast height, total height and crown length as independent variables. Main results. Total tree biomass in forests was 240.58 Mg ha-1 in the young forest and 411.30 Mg ha-1 in the aged forest with a low root/shoot ratio (0.41 for young forest and 0.31 for aged forest). Total stored carbon was 419.46 Mg C ha-1 in the young forest and 658.09 Mg C ha-1 in the aged forest. Carbon stock (Mg C ha-1) was estimated to be113.61 (27.08%) and 194.08 (29.49%) in trees, 3.55 (0.85%) and 5.73 (0.87%) in litter and 302.30 (72.07%) and 458.27 (69.64%) in soil in the young and aged forests, respectively. Research highlights. Aged undisturbed forest had the largest tree biomass but a lower potential for accumulation of carbon in the future; in contrast, young disturbed forest had both higher growth and carbon storage potential.
The objective of this study was to determine if various morphological components of height growth... more The objective of this study was to determine if various morphological components of height growth were sensitive to environmental factors (i.e., grass root competition, frost and shading) and to see if these components could be used to quantify the effect of environmental stress on the height growth of sessile oak (Quercus petraea Liebl.) seedlings. The following components were measured: number of flushes produced on the main stem, length of the growth unit (GU) developed during each flush, annual GU length, number of nodes per GU, and state of the terminal bud of each GU. The number of flushes produced was reduced by all environmental treatments. The annual GU length was positively related to the number of flushes produced. Grass competition reduced GU length in each flush and therefore reduced annual GU length. On the other hand, partial shading increased GU length in each flush and annual GU length. Number of nodes was not apparently affected by environmental factors and was positively related to GU length. Where factors that affect terminal bud mortality were partially controlled (i.e., in grass competition and shading experiments), mortality rate was low (5% for GUS of the first flush in grass competition experiment), but in the frost experiment terminal bud mortality rate was higher (64% for GUS of the first flush). The sensitivity of the different morphological components to environmental factors and the quantification of the effects of the factors using generalized linear models were discussed. 0 1997 Elsevier Science B.V.
Canadian Journal of Botany-revue Canadienne De Botanique, 1999
Seed sowing, planting or vegetative propagation after felling are used to reconstitute the vegeta... more Seed sowing, planting or vegetative propagation after felling are used to reconstitute the vegetation cover. Sometimes, the first two methods end up being ineffective and costly. Terrestrial layering and suckering provide an interesting alternative in some areas. In semiarid regions mainly, it is necessary to have a better knowledge of the vegetative propagation process. To that end, launching specific case studies on key species from these areas should be initiated.
Aim of the study. To estimate biomass and carbon accumulation in a young and disturbed forest (re... more Aim of the study. To estimate biomass and carbon accumulation in a young and disturbed forest (regenerated after a tornado) and an aged cork oak forest (undisturbed forest) as well as its distribution among the different pools (tree, litter and soil). Area of study. The north west of Tunisia Material and methods. Carbon stocks were evaluated in the above and belowground cork oak trees, the litter and the 150 cm of the soil. Tree biomass was estimated in both young and aged forests using allometric biomass equations developed for wood stem, cork stem, wood branch, cork branch, leaves, roots and total tree biomass based on combinations of diameter at breast height, total height and crown length as independent variables. Main results. Total tree biomass in forests was 240.58 Mg ha-1 in the young forest and 411.30 Mg ha-1 in the aged forest with a low root/shoot ratio (0.41 for young forest and 0.31 for aged forest). Total stored carbon was 419.46 Mg C ha-1 in the young forest and 658.09 Mg C ha-1 in the aged forest. Carbon stock (Mg C ha-1) was estimated to be113.61 (27.08%) and 194.08 (29.49%) in trees, 3.55 (0.85%) and 5.73 (0.87%) in litter and 302.30 (72.07%) and 458.27 (69.64%) in soil in the young and aged forests, respectively. Research highlights. Aged undisturbed forest had the largest tree biomass but a lower potential for accumulation of carbon in the future; in contrast, young disturbed forest had both higher growth and carbon storage potential.
The objective of this study was to determine if various morphological components of height growth... more The objective of this study was to determine if various morphological components of height growth were sensitive to environmental factors (i.e., grass root competition, frost and shading) and to see if these components could be used to quantify the effect of environmental stress on the height growth of sessile oak (Quercus petraea Liebl.) seedlings. The following components were measured: number of flushes produced on the main stem, length of the growth unit (GU) developed during each flush, annual GU length, number of nodes per GU, and state of the terminal bud of each GU. The number of flushes produced was reduced by all environmental treatments. The annual GU length was positively related to the number of flushes produced. Grass competition reduced GU length in each flush and therefore reduced annual GU length. On the other hand, partial shading increased GU length in each flush and annual GU length. Number of nodes was not apparently affected by environmental factors and was positively related to GU length. Where factors that affect terminal bud mortality were partially controlled (i.e., in grass competition and shading experiments), mortality rate was low (5% for GUS of the first flush in grass competition experiment), but in the frost experiment terminal bud mortality rate was higher (64% for GUS of the first flush). The sensitivity of the different morphological components to environmental factors and the quantification of the effects of the factors using generalized linear models were discussed. 0 1997 Elsevier Science B.V.
Canadian Journal of Botany-revue Canadienne De Botanique, 1999
Seed sowing, planting or vegetative propagation after felling are used to reconstitute the vegeta... more Seed sowing, planting or vegetative propagation after felling are used to reconstitute the vegetation cover. Sometimes, the first two methods end up being ineffective and costly. Terrestrial layering and suckering provide an interesting alternative in some areas. In semiarid regions mainly, it is necessary to have a better knowledge of the vegetative propagation process. To that end, launching specific case studies on key species from these areas should be initiated.
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