Northern Forest Futures Project


[image:] An ash leaf in fall colors

Ecosystem Health and Vitality

Forest ecosystem health depends on stable forest composition and structure and on sustainable ecosystem processes. Forest disturbances – disease, insects, climate, destructive weather events and fire, to name a few -- that push an ecosystem beyond the range of conditions considered normal can upset the balance among processes, exacerbate forest health problems, and increase mortality beyond historical norms.

Key Findings

  • Forest threats like emerald ash borer, hemlock woolly adelgid, beech bark disease, and gypsy moth are causing major changes to forests.
  • Insects such as the Asian longhorned beetle, spruce budworm, Sirex woodwasp, and winter moth have exhibited the potential to decimate a variety of tree species and could become more formidable to forests in urban and rural areas.
  • Emerald ash borer could decimate the entire U.S. population of ash, which is culturally significant to Native American populations, valuable for specialty products, and valued in urban landscapes.
  • Decline-disease complexes such as oak decline are causing negative ecological and economic effects.
  • Fire regime changes have substantially decreased the abundance of fire-tolerant and fire-adapted vegetation like oaks and have contributed to invasion by fire-intolerant mesic species.
  • Invasive plants are contributing to habitat loss, ecosystem degradation, and decreasing species diversity.
  • Other threats such as deforestation and fragmentation contribute to worsening forest health conditions, which provide increased opportunities for invasions
    to spread.
  • Although forest threats have always existed, present-day challenges to forest ecosystem health, diversity, and resilience are unprecedented

From Future forests of the northern United States, NRS-GTR-151, 2016.

Maps and Figures

[map:] Occurrence and future risk of gypsy moth infestation in the North
Occurrence and future risk of gypsy moth infestation in the North, estimated by volume of host tree species.
[map:] Forest land ownership in Northern States
Spatial distribution of emerald ash borer occurrence and susceptibility as a function of preferred host range, presence of urban ash trees, proximity of urban ash trees to natural forests, and past rates of phloem insect interceptions at U.S. ports of entry; susceptibility is defined as the potential for introduction and establishment of a forest pest within a tree species or group

For additional detail, see Criterion 3: Maintenance of forest ecosystem health and vitality in the Future forests of the northern United States.