Heterobasidion Root Disease , H. occidentale, H. irregulare Contributions by: Pete Angwin, Beverly Bulaon, Joel Egan, Martin Mackenzie and Paul Zambino

Heterobasidion root disease (formerly annosus root disease) caused scattered pockets of mortality in white of all sizes throughout the 15 acre McBride Springs Campground on M261D the Shasta-McCloud Management Unit, Shasta-Trinity National Forest (Siskiyou County, M261D). Fruiting bodies were found in four white fir stumps. Fir engraver beetles (Scolytus ventralis) attacked and killed the larger root-disease-infected fir. Because of the hazard posed by the presence of the root disease, the campground was closed for the 2009 season, pending management action.

White fir stumps scattered throughout the ten acre Carter Meadows Horse Camp (Siskiyou County, M261A) had hollow interiors and laminant decay, typical of heterobasidion root M261A disease, and a Heterobasidion occidentale fruiting body was found in one of these stumps. Although the remaining standing white fir have rounded tops, they show no additional symptoms of root disease. Dead and dying are removed annually from this Figure 40: White campground; the presence of symptomatic fir stump with stumps throughout the area suggests that fruiting body of the disease is widespread. Heterobasidion annosum at Pingri- La Resort, west of Scattered heterobasidion root disease Castella, California. centers are present in approximately five Photo: P. Angwin acres of white fir above the visitor cabins at the private Pinegri-La Resort, 11.5 miles west of of Castella (Shasta County, M261A). H. occidentale fruiting bodies were found in four stumps. Fir engraver beetles have attacked and killed many of the root diseased firs.

Heterobasidion root disease caused scattered pockets of mortality in white fir throughout the 37 acre Unit 160 of the Figure 41: White fir killed by Elk Late Successional Reserve, Shasta- Heterobasidion McCloud Management Unit, Shasta-Trinity root disease and National Forest (Siskiyou County, M261D). fir engraver beetle at McBride Spring Groups of white fir blowdown had laminant Campground, Shasta- decay in the roots and fruiting bodies of Trinity NF. Heterobasidion occidentale were found in Photo: P. Angwin three stumps. Fir engraver beetles were also present in the dead and dying white fir.

Heterobasidion root disease in true fir continued to impact high-value recreation and administration sites in the south Sierra Nevada range. Mortality had an average rate of one tree every two acres near Pinecrest Lake in recreation-residence areas, Cow Creek housing tracts, and M261E Baker Campground on the Stanislaus National Forest (Tuolumne County, M261E). A mortality pocket of 20 red fir was located ten miles north of Strawberry along State (see reportonCaliforniaflatheadedborer, page20). Ridge on the Mt. Pinos Ranger District, Los Padres National Forest (Kern County, M262B) ( borer flatheaded California by caused mortality Jeffrey continued the to contributed likely and present was disease ponderosae County, M262B), Bernardino (San and Forest likely National contributed Bernardino San to Trailhead, Crest their Cougar attack the by near pine mountain pine beetle ( Heterobasidion root disease was found in stumps of several windthrown single-leaf pinyon indicate thebrushasapotentialsourceofinoculum. of hosts ( rabbitbush and sp.) ( Sage seedlings. pine Jeffrey planted of mortality heavy was there remained, acre infection center where mature pinyon and Jeffrey pine had been killed and only brush five one In (VenturaCounty,M262B). Forest National Padres Los District, Ranger Pinos by fir-infecting the was scars fire the in the if one root rot pocket had abundant stringy rot typical of the bole. Also, beneath dead bark, fire scars caused by underburns on five living white fir in of fallen trees of both species had stringy rot and were broken at major roots very close to On the Chula Vista Trail, both Jeffrey pine and white fir had heterobasidion root rot. windthrow Pockets of six large Jeffrey Forest at scattered National locations in Padres the Mount McGill Los Campground. District, Ranger (Ventura County, Pinos M262B). Stringy rot, caused Mt. by Trail, Vista Chula the near and There were new detections of heterobasidion root disease at the Mount McGill Campground found, indicatingthatfungiinthisisolatedstumpwerelikelysporulatingfordecades. of classes age distinct early the Three in felled been have 1980s. County, to estimated was that stump fir red DBH 60” a in M261E) (Amador Forest National Eldorado the on 88 Hwy State along found were bodies fruiting disease root occidentale Heterobasidion been also attacked bythefirengraver. had most had and they disease root Heterobasidion that indicated examined were that fir (Fresno dying the of All M261E). Forest County, National Sierra Basin, Huntington the overstory throughout dying trees fir many red are addition, In there disease. root Heterobasidion with infected stumps to adjacent 108 Hwy of H. irregulare H. H. occidentale H. Heterobasidion (e rpr o muti pn bel, ae 0.As, eeoaiin root heterobasidion Also, 10). page beetle, pine mountain on report (see ) were still active at the Mil Potrero Boy Scout Camp, Mil Potrero Road, Mt. Road, Potrero Mil Camp, Scout Boy Potrero Mil the at active still were that might affect adjacent legacy Jeffrey pine. Historic infection centers infection Historic Jeffreypine. legacy affectadjacent might that Chrysothamnus sp. Roots of large dying clumps of sage had delamination that delamination had sage of clumps dying large of Roots sp.

Melanophila californica Melanophila sp.) predominate in the brush field; both are known are both field; brush the in predominate sp.) eeoaiin occidentale Heterobasidion Heterobasidion irregulare H. irregulare H. Heterobasidion ) along Pine Mountain and Tecuyaand Mountain Pine along ) or saprophytic colonization saprophytic or riig ois were bodies fruiting sp. It was unknown , contributed to Dendroctonus Artemisia Photo: J.Egan host treewasfelled. 20-30 yearssincethe fir stumpestimatedat a large-diameterred reproductive conksin occidentale Heterobasidion age classesofviable, Figure 42: Three M262B M261E

Diseases