Survey of damaging pests and preliminary assessment of forest health risks to the long term success of Pinus radiata introduction in Sichuan, southwest China

Abstract

Pinus radiata was introduced to the summer rainfall environments of Sichuan Province, China in the 1990s as a part of an afforestation program for soil and water conservation in the arid and semi-arid river valley area of Aba Prefecture. Within this region a total area of 26 000 ha have been identified through climate matching as suitable and a further 63 000 ha potentially suitable for environmental plantings of P. radiata. The plantations are being established in widely separated small patches on steep and degraded slopes along the dry river valley. The newly introduced P. radiata are exposed to two kinds of forest health risks: they may be attacked by (a) indigenous pathogens and pests against which they may not possess any resistance or (b) by inadvertently introduced foreign pests or pathogens. This paper presents a survey of the potential damaging pests and a preliminary assessment of forest health risks facing the P. radiata plantations over a much longer timeframe than the initial phase of introduction and early plantation establishment. An empirical approach was adopted to evaluate forest health risks by a combination of literature review, examination of historical records of pest and disease outbreaks in the surrounding coniferous forests, field surveys and inspections, specimen collection and identification, and most importantly, expert analysis of the likelihood of attack by specific pests and pathogens and the subsequent impact of such attacks. The assessment identified some specific forest health risks to the long-term success of P. radiata introduction in this area. These risks are closely associated with the indigenous pests and pathogens of the two native pine species, P. tabulaeformis and P. armondii since these pests and pathogens are considered more likely to establish on P. radiata over time. Exotic pests and pathogens are of a quarantine concern at present. Based on the results of assessment, recommendations are provided to improve forest vigour and to reduce the forest health risks posed by indigenous as well as exotic pests and pathogens to the introduced P. radiata. Ways to increase the ability to manage the forest health risks once a particular pest infestation and disease eventuates are also recommended. Although detrimental to the survival and growth of the introduced P. radiata, the impact of identified forest health risks are not considered to be fatal to the long term success of P. radiata in this area.

European gypsy moth (Lymantria dispar dispar L.) completes development and defoliates exotic radiata pine plantations in Spain

“…These reports, although limited, are important since they suggest that radiata pine plantations elsewhere in the world could be at risk from European gypsy moth. However, most previous concern about potential impacts of gypsy moths on radiata pine plantations have focused on the risk associated with invasions by Asian gypsy moth subspecies (Walsh 1993;Matsuki et al 2001;Withers and Keena 2001;Pitt et al 2007;Bi et al 2008;Troncoso 2012).…”

Additive prediction of aboveground biomass for Pinus radiata (D. Don) plantations

“…With a total global area now exceeding 4.3 million hectares and still expanding, it is a major species for timber production in Australia, Chile, New Zealand, South Africa and Spain (Lewis and Ferguson, 1993;Lavery and Mead, 1998;Sutton, 1999;Toro and Gessel, 1999;Rogers, 2002). Besides commercial plantations, it has emerged to be a suitable species for environmental plantings on steep and degraded mountain slopes in southwest China (Bi et al, 2003;Yan et al, 2006;Bi et al, 2008). The worldwide P. radiata resource provides a substantial storage for carbon through continued carbon sequestration as plantations grow and accumulate biomass.…”

Insect pests in tropical forestry

“…Tree shape is unimportant for fuelwood, but straight stems are desirable in trees destined for wood pulp to aid in rapid debarking. Insect attack which results in malformation of stems, for example, Dioryctria rubella (Lepidoptera: Tortricidae) shoot moth attack on Pinus radiata in southern China (Bi et al, 2008) and wood moth attack on leaders of plantation eucalypts in Sumatra (Plates 72 and 73), can thus lower the value of the crop. There is a general tendency among forest managers to underestimate the impact of pest attacks which do not result in outright tree mortality, particularly where the crop is destined for pulp.…”

“…At least, though, this type of resistance system may well have a role to play as part of an IPM programme, where resistance can be combined with other forms of control such as biological or chemical (see Chapter 10). Bi et al (2008) present a list of recommendations to be adopted at the planning stage of a tropical forest plantation, based on experiences in south-west China, much of which we have discussed in previous sections of this chapter. Their first criterion reintroduces the concept of forest health, and the second the practice of pest and disease surveillance, i.e.…”