Incorporating Sectoral Structure into Shift–Share Analysis

The objective of this article is to present a new way to incorporate the sectoral dimension within the components of regional growth provided by the traditional shift–share analysis. The new methodology elaborates the way that the dynamics of a specific sector in a region are influenced by the performance of other sectors, the latter decomposed between national, structural, and differential effects. To illustrate this extension of the shift–share method, an application is provided using data for the Spanish region of Extremadura for the period 1990–2004. The results highlight how these new components can shed new insights into the analysis of sectoral and regional economic growth processes.     

Cooperative breeding for the northern marginal areas

Summary A joint breeding project for the northern areas of Scandinavia and Iceland was initiated in 1981 under the auspices of the Nordic Council of Ministers. Initially, efforts concentrated on cooperative trials in which both early and more advanced breeding material was tested at a number of experimental stations in the northern regions. This was followed by a joint breeding programme for timothy with the primary aim of developing varieties that possess broad adaptation to a range of Nordic climates and managements and can be grown throughout the northernmost part of Scandinavia. Each of the five national breeding stations originally provided 12 timothy genotypes for the project giving a total of 60 genotypes. The parental genotypes were compared as spaced plants at all five stations and their polycross progeny were grown under sward conditions at the same sites. On the basis of results obtained from these field trials parent clones have been selected and intercrossed to form synthetic populations.     

When structure means conservation: Effect of aggregate structure in controlling microbial responses to rewetting events

Rewetting events after a drought produce a pulse of soil respiration (the “Birch Effect”) that leads to a loss of carbon from soil, especially in Mediterranean ecosystems. Two main hypotheses have developed to explain the Birch effect: the “metabolic explanation”, based on the rapid consumption of intracellular osmolytes previously accumulated to survive to dry conditions, and the “physical explanation”, based on the consumption of carbon made accessible by physical destruction of internal structures of the soil.Here, we compared the respiration response of intact and crushed 9–4 mm aggregates from a California grassland soil under two different rewetting schemes: (1) successive short dry/wet events and (2) increased drought periods followed by a single rewetting. In intact aggregates, both microbial biomass and respiration rates were relatively stable through both experimental treatments. In crushed aggregates, through multiple short dry/wet cycles, both respiration rate and microbial biomass increased, while as drought length increased, biomass was unaffected but the magnitude of the following rewetting pulse increased. A mechanism that explains both these results is that crushing aggregates exposes occluded particular material that must be degraded into an immediately bioavailable form for microbes to take it up and metabolize it. Nitrification was generally higher in intact than crushed aggregates, suggesting the importance of physical association between nitrifiers and resources in regulating overall soil nitrification.This work suggests that physical processes are most important in driving respiration pulses through multiple rewetting cycles and that the physical association of organisms, substrates, and mineral particles are critical in controlling the functioning of the “microbial landscape”.     

Phenological and water-use patterns underlying maximum growing season length at the highest elevations: implications under climate change

Consequences of climate change on tree phenology are readily observable, but little is known about the variations in phenological sensitivity to drought between populations within a species. In this study, we compare the phenological sensitivity to temperature and water availability in Abies pinsapo Boiss., a drought-sensitive Mediterranean fir, across its altitudinal distribution gradient. Twig growth and needle fall were related to temperature, precipitation and plant water status on a daily scale. Stands located at the top edge of the distributional range showed the most favourable water balance, maximum growth rates and little summer defoliation. Towards higher elevations, the observed delay in budburst date due to lower spring temperatures was overcome by a stronger delay in growth cessation date due to the later onset of strong water-deficit conditions in the summer. This explains an extended growing season and the greatest mean growth at the highest elevation. Conversely, lower predawn xylem water potentials and early partial stomatal closure and growth cessation were found in low-elevation A. pinsapo trees. An earlier and higher summer peak of A. pinsapo litterfall was also observed at these water-limited sites. Our results illustrate the ecophysiological background of the ongoing altitudinal shifts reported for this relict tree species under current climatic conditions.     

Influence of provenance,silvicultural regime and tree shape on the quality of maritime pine (Pinus pinaster) timber

The aim of this study was to establish the sources of variation in maritime pine wood properties related to appearance and strength, because of the importance of this wood in the sawing industry in Galicia (NW Spain). Ten trees from each of ten plots of the species (i.e., 100 trees) growing in Galicia were felled and sawn to produce the structural planks required for studying the presence of external strength-reducing characteristics. The planks were sampled from the basal logs to 16 m height in the stems, yielding cross sections of target dimensions 100 × 40 mm to 200 × 200 mm. We propose a model in which individual tree height and dominant height are used to predict the knottiness of planks from trees in mature stands. The abundance of externally visible knots on faces and edges of sawn planks is therefore more dependent on the stand location than on the prior silvicultural treatment of the stand.     

Mini‐cutting technique application in Corymbia and Eucalyptus: effects of mini‐tunnel use across seasons of the year

New Forests - The forestry sector has been able to sustainably satisfy the increasing global demand for forest products, thereby positively impacting the economy, while mitigating climate change....     

How much do Irish Private Forest Owners Know about Forestry?

Since 1980, over 20,000 Irish landowners have afforested land, for the first time, as part of an afforestation programme subsidised by the Government and the EU. A survey of 99 private forest owners was conducted to determine their knowledge of broad aspects of forest management. Key questions were scored so as to test whether respondents had passed or failed a forestry knowledge test. Over two-thirds of private forest owners passed the test. Success in this test was shown to be related to whether respondents had (a) attended extension field days; (b) been active in forest operations in the early stages of the forest cycle and (c) been members of farming and/or forestry groups. Younger respondents (i.e., ≤50 years) were more likely to pass the knowledge test than older respondents.     

Relating growth and nutrition to site factors in young chestnut plantations established on agricultural and forest land in northern Spain

The growth and nutritional status of 97 hybrid chestnut plantations on former agricultural land and forest land were studied in relation to site conditions (climatic variables and soil properties). A single family of curves was obtained for classifying the early height growth of hybrid and sweet chestnut. Soil limitations and nutrient deficiencies were evident in the former forest land, whereas the agricultural soils were found to be generally suitable for growing chestnut. The stands with highest growth rates were characterized by high foliar concentrations of K, P and Ca. Successful growth of the plantations was always related to high summer precipitation, low elevation and absence of long periods of risk of frost. The results confirm the adaptability of chestnut to most sites where it has been planted for timber production.     

Multiple trait genetic evaluation of ewe traits in Icelandic sheep

The prolificacy of the ewes was measured as the number of lambs born per ewe mated (NLB) when the ewes were 1–4 years of age. The ewe productivity related to the same age interval was measured by special ewe production indices (EPI). The genetic parameters for these traits were estimated by a series of bivariate REML analyses using animal models. The material used for the genetic analysis contained records on 193 213 ewes. The heritability estimates for NLB were h² = 0.17, 0.13, 0.11, 0.10 for the four respective age classes. Corresponding estimates for EPI were h² = 0.16, 0.17, 0.17, 0.15. The genetic correlations among NLB at different ages ranged from 0.63 to 0.98 and among EPI from 0.82 to 0.99. The genetic correlations between NLB and EPI were generally low. The material used for estimating the breeding values by the MT‐BLUP Animal Model consisted of 1.5 million individuals in the pedigree file. In total 815 782 ewes had records for the NLB and 763 491 ewes had production index (at least 1 year). The records were registered in the years 1990–2006. All possible missing patterns were present in the data. In the iteration process expected values for missing traits were generated and solutions were obtained on canonical transformed scale. The genetic evaluations were run independently for NLB and EPI for computational convenience given the correlations between these traits were negligible.