Thorbergur Jonsson

Abstract Urban street trees are often overlooked as essential contributors to the total urban canopy. The city centre of Reykjavik, Iceland was surveyed using random plots throughout the central portion of Reykjavik to determine species composition, structure, potential conflicts with infrastructure, and environmental benefits. In this portion of Reykjavik, 11 tree species were observed, dominated by Populus trichocarpa. For all species, the density was approximately 67 trees/km, which when compared with other Nordic cities was quite high. However, in terms of number of species, diversity was much lower compared to other Nordic cities. Street trees in this portion of the city sequester approximately 793 Mg of carbon. Value to the city summed to 15,764,000 ISK (134,000 USD), which partitioned to 187,000 ISK per kilometer or 128 ISK per capita. There were also conflicts identified with buildings and with sidewalks buckling, particularly with P. trichocarpa. Given the density and value of the trees in this portion of Reykjavik, it is imperative for additional work to be undertaken to manage the urban canopy and mitigate any costs associated with conflicts between trees and infrastructure throughout the city.

A study was compiled to quantify organic carbon stock in reclaimed ecosystems in Iceland. The objective of this paper is to report the carbon mass in vegetation of such systems and to assess its contribution to total carbon sequestration. Organic carbon stock was measured in three components, i.e. in aboveground and belowground biomass, and soil on land with different conditions and under different reclamation methods. The study shows that reclamation of degraded land results in organic carbon sequestration and that a part of the sequestration is in the biomass. The annual rate of sequestration in aboveground biomass ranged from 0.01 to 0.5 t C ha–1, the amount depending on the reclamation method used and site conditions. More comprehensive dataset on carbon sequestration under diverse conditions is, however, needed to use as basis for modelling of organic carbon sequestration. These results show that reclamation measures designed to restore the ecological potential of degraded land...

Veruleg afföll eru á ungum trjáplöntum hérlendis eftir gróðursetningu. Þau eru oft mikil fyrsta sumarið þegar rætur plantnanna ná of skammt út í jarðveginn til að draga sér nægt vatn. Vökvun með glycinebetaine hefur reynst góð aðferð til að auka þurrkþol ýmissa ...

Maritime tree limits are rarely defined or addressed in the scientific literature. It has been proposed that mari-time tree limits are ultimately set by airborne salt inducing top shoot dieback. The maritime tree limit would then be at the point of zero average net height ...