SFTT Meeting: 1 November 2017

Update on

Phytophthora ramorum on larch in Scotland

Hugh ClaydenForestry Commission Scotland

Ramorum on larch (cont)Approx. area of larch (2012):

FES 26,000 haPvt 39,000 ha

Total: 65,000 ha

Standing volume (2011):

FES 4.8 M m3

Pvt 12.6 M m3

Total: 17.4 M m3 (~ 250 m3 /ha)

Year No. larch SPHNs Ha larch under SPHN

2010 1 22011 3 162012 18 542013 53 2262014 16 542015 35 932016 61 2162017 47 (Provisional) 63 (Provisional)

Total 234 724

+

6-7k ha of larch with assumed infection

Av. Size

3 ha

Each dot = 500 ha

Number of suspicious sites reported in 2017

Via helicopter: 388 (8% +ve for Ramorum)

Ground sightings: 108 (29% +ve for Ramorum)

Ramorum on larch (cont)Why continue with SPHNs?

• Legal requirement

• ~ 99% larch outside the Management Zone is not known to be infected

• Have not seen a repeat of 2012/2013 surge

• Reduce threat to adjacent tree species e.g. SS, WH, DF, GF

• Phased market entry: harvesting resource remains available; market

development/maintenance; avoid significantwhitewood displacement (UKWAS issue)

• Tree health grant support available (but not in Management Zone)

• Reduce scale of visual and environmental (water, wildlife) impacts

• Reduce pest and fire risks

• Buy time for potential alternative treatments to emerge

• External confidence – investors, public, political

• The Phytophthora factor

• STHAG advice

• 170 Phytophthoras currently known world-wide

• Could be as many as 500

• 42 known to be present in UK, a third beingpathogenic on woody species

• Recent work by FR & JHI at 15 ‘disturbed sites’ in Scotland detected 20 species, including 3 not previously recorded in the UK and 1 unknown species

Phytophthora alni

(P. cambivora x P. fragariae)

Ramorum on R. ponticum

Year No. R. ponticum SPHNs Ha R. ponticum under SPHN

2010 0 0

2011 3 3

2012 1 0.2

2013 1 0.1

2014 2 0 (both on Larch sites)

2015 2 0.2

2016 24 4

2017 55 13

Total 88 21

Replanting after Ramorum

Phytophthora - advice to owners, agents and industry:

www.forestry.gov.uk/forestry/infd-868egu

Replanting after Ramorum

FES Larch Strategy

Dendroctonus micans

Chalara