Seasonal variation in moisture content of eastern Canadian tree foliage and the possible effect on crown fires
Document Type: Book
Author(s): C. E. Van Wagner
Publication Year: 1967

Cataloging Information

  • Abies balsamea
  • Acer saccharum
  • Canada
  • coniferous forests
  • conifers
  • crown fires
  • energy
  • fire management
  • flammability
  • foliage
  • forest management
  • fuel moisture
  • hardwood forests
  • hardwoods
  • heat
  • Juniperus
  • Kalmia latifolia
  • leaves
  • moisture
  • old growth forests
  • Picea glauca
  • pine forests
  • Pinus banksiana
  • Pinus edulis
  • Pinus ponderosa
  • Pinus resinosa
  • Pinus strobus
  • Populus tremuloides
  • sampling
  • seedlings
  • trees
  • wildfires
Record Maintained By:
Record Last Modified: June 1, 2018
FRAMES Record Number: 39173
Tall Timbers Record Number: 13807
TTRS Location Status: In-file
TTRS Call Number: CAN Docs DDW
TTRS Abstract Status: Okay, Fair use, Reproduced by permission

This bibliographic record was either created or modified by the Tall Timbers Research Station and Land Conservancy and is provided without charge to promote research and education in Fire Ecology. The E.V. Komarek Fire Ecology Database is the intellectual property of the Tall Timbers Research Station and Land Conservancy.


Foliar moisture content was sampled in five eastern Canadian conifers and two hardwoods during 1962-65, and seasonal trends were estabished. These were basically similar from year to year despite weather differences. The moisture content of new conifer foliage and hardwood foliage was very high (over 300 per cent) at flushing, decreased sharply, and gradually levelled out by late summer. The moisture content of old conifer foliage fell during April, passed through a minimun (ca. 95 per cent) in May and early June, then rose gradually to a maximum (ca.115 per cent) in late summer. The average composite foliar moisture content of the five conifers rose from about 95 per cent in late May and early June to about 130 per cent in mid-August. Theoretical speculations based on the heat energy required to drive off differing amounts of foliar-moisture, as well as the results of laboratory flammability tests with single trees, suggest that the 35-point difference probably has a distinct effect on the behaviour of crowning forest fires.

Van Wagner, C. E. 1967. Seasonal variation in moisture content of eastern Canadian tree foliage and the possible effect on crown fires. Departmental Publication No. 1204. Ottawa, Canada Department of Forestry and Rural Development, Forestry Branch.