Suillus brunnescens is a widespread Suillus in western North America, occurring with five-needle pines across the western mountains.

Five-needle pines are suffering decline from the introduced fungal pathogen White Pine Blister Rust (Cronartium ribicola), and subsequent attacks by the Mountain Pine Beetle (Dendroctonus ponderosae).

Suillus brunnescens was described based on a Type collection made near Grants Pass, Oregon, USA (Smith & Thiers 1964)

Suillus borealis (Smith et al. 1965), described from Idaho is a synonym (Nguyen et al. 2017).

Suillus brunnescens is a widespread Suillus in western North America, occurring with five-needle pines across the western mountains.

Five-needle pines are suffering decline from the introduced fungal pathogen White Pine Blister Rust (Cronartium ribicola), and subsequent attacks by the Mountain Pine Beetle (Dendroctonus ponderosae).

Assessment needs to decide if the scale of decline is at a level over three generations of an ECM fungus to warrant listing at NT.

Widespread in the mountain of western USA; from the southern Sierra Nevada in California, north through the Siskiyou mountains and Cascade Range throughout the Pacific Northwest, east across the northern Rocky Mountains into southern Canada.

Suillus brunnescens is locally common and widespread in western North America, occurring with five-needle pines across the western mountains. However, many five-needle pine species are declining due to the introduced fungal pathogen White Pine Blister Rust (Cronartium ribicola).

Ectomycorrhizal with five needle pines; especially Sugar Pine (Pinus lambertiana) in California, and Western White Pine (P. monticola) in the Pacific Northwest. Fruiting in summer and fall, with young to mature trees.

Many five-needle pine species are declining due to the introduced fungal pathogen White Pine Blister Rust (Cronartium ribicola), and subsequent attacks by the Mountain Pine Beetle (Dendroctonus ponderosae).

Prolonged droughts and decades of fire suppression have drastically altered western montane forests, leading to thicker, denser, Abies dominated forests. As a result, hotter, stand replacing fires (rather than patchwork and understory burns) are commonplace, altering appropriate habitat drastically, and making it ill-suited for this species.

Continued work on breeding blister rust resistant pines, and control of blister rust spread.

Extent of range and tree association of this species.

Suillus species are edible, but are not highly regarded, and thus only occasionally collected.

Nguyen, N., E.C. Vellinga, T.D. Bruns & P. Kennedy. 2017. Phylogenetic assessment of global Suillus ITS sequences supports morphologically defined species and reveals synonymous and undescribed taxa. Mycologia 108: 1216–1228.

Smith, A.H. and Thiers, H.D. 1964. A Contribution Toward A Monograph of North American Species of Suillus. University of Michigan Press. Ann Arbor, MI. 116 p.

Smith, A.H., Thiers, H.D. and Miller, O.K. 1965. The species of Suillus and Fuscoboletinus of the Priest River Experimental Forest and vicinity, Priest River, Idaho. Lloydia 28:120–138