The Economic Factors which Influence the Type of Timber Grown and the Methods of Growing it

The most important decision to be taken is the decision whichleads to the initial investment. In private forestry, deathduties continue a powerful factor in economics. In the ForestryCommission it could be argued that, after abandonment of theneed to form a strategic reserve, interest-earning capacitywas the main reason for investment and that the Faustmann testshould be applicable but this would imply that afforestationwas competing freely with other new investments which is notso. The specifications of firm buyers are likely to determinethe type of timber grown and the technical rotation to takeprecedence over all others. As buyers' specifications change,management must be flexible with, the writer considers, a biasin favour of high quality rather than low.     

Phytophthora oleae,a new root pathogen of wild olives

Wild olive (Olea europaea subsp. europaea var. sylvestris) is an important component of Mediterranean forests and a key genetic source for olive improvement programmes. Since 2009, a severe decline caused by Phytophthora cryptogea and P. megasperma has been detected in a protected wild olive forest of high ecological value (Dehesa de Abajo, Seville, Spain). In this natural forest, sampling of roots and soil was carried out on 25 wild olives with symptoms in 2014 and 2015. Apart from the already known P. cryptogea A1 and P. megasperma, a third Phytophthora species was consistently isolated from wild olive rootlets with symptoms. These isolates conformed morphologically with the newly described species P. oleae and were confirmed by analysis of their ITS regions and cox1 sequences. Temperature–growth relationships showed a maximum growth at 19.9 °C on carrot agar medium, making it the lowest temperature Phytophthora species infecting wild olive roots. Pathogenicity was confirmed on 1-year-old healthy wild olive seedlings and was similar to the previously known pathogenic phytophthoras. As temperature requirements are quite different, the three Phytophthora species may be active against wild olive roots in different seasons. However, the prevalence of P. oleae infecting wild olives in recent years could be due to its introduction as a new invasive pathogen. The probable invasive nature of P. oleae, together with increasing rain episodes concentrated in short periods frequent in southern Spain, would allow the outbreak of infections in wild olive forests, and also put cultivated olive orchards at risk.