OF1 — White spruce / Aster – Goldenrod / Shaggy moss (n=25)
OF2 — Tamarack / Speckled alder / Rough goldenrod / Shaggy moss (n=7)
OF3 — White pine – Balsam fir / Shinleaf – Pine-sap (n=10)
OF4 — Balsam fir – White spruce / Evergreen wood fern – Wood aster (n=7)
OF5 — Trembling aspen – Grey birch / Rough goldenrod – Strawberry (n=11)
Concept: These are forests originating on abandoned farmland where soils have been enriched through the addition of organic matter by tillage or grass cover (pasture). Vegetation Types (VT) are early successional and typically dominated by softwood species. Old field VTs usually develop full overstory canopies with sparse understory cover and a needle carpet or moss dominated forest floor. These are short-lived, even-aged forests which often succumb to insects and disease. All VTs in this group are found in the Acadian Ecosite group, with several also found in the Maritime Boreal Ecosite group.
Vegetation: These closed canopy forests are typically dominated by white spruce, tamarack, white pine or balsam fir. An aspen dominated VT has also been identified. Red oak and white ash can sometimes be found on richer old field sites, but no separate VT has been described for this situation. Both the shrub and herb layers can be species diverse, but they are usually poorly developed. Herbs associated with agricultural lands are common. Schreber's moss and shaggy moss are the main bryophytes found where needle carpet or leaf litter do not dominate the forest floor.
Environmental Setting: Vegetation types in this group are found on a range of slope positions. Many sites have been cleared of surface rocks which have been piled or arranged as walls along property lines. Soils are mainly derived from glacial till deposits and usually have a distinctive Ap (plough layer) horizon caused by tilling or pasture cover. This organically enriched Ap horizon may be less well developed (or even absent) on some old pasture sites. Microtopography is also usually smooth (level) where tilling has occurred. A wide range of moisture levels can be found, but fertility is generally medium to rich throughout. These forests are found throughout the province, but are most common on the Nova Scotia Uplands (300) and Fundy Shore (900) ecoregions, and on drumlins in the Clare (730) and LaHave Drumlins (740) ecodistricts.
Successional Dynamics: Old field forests are early successional VTs that develop on sites modified by clearing and agricultural use. Clearcut harvesting of mature stands is likely to initiate another early successional stage dominated by shade-intolerant hardwood species such as grey birch, aspen, pin cherry and white birch. Stands that slowly deteriorate may provide more opportunity for shade-tolerant species to become established if seed sources are nearby. It is expected that several rotations will be needed before original forest conditions become re-established on most old field sites in the province.
Ecological Features: Since the early 1900's, large areas of abandoned agricultural land have reverted to early successional softwood forest. These distinctive patches add structural diversity to the landscape, often providing strong transitional zones between fields and natural hardwood forests. These ecosystems are relatively simple, frequently dominated by one tree species with minimal understory development. Following stand collapse or harvesting some species indicative of pre-farming stand composition may develop in the next successional stage, but several rotations are required before pre-agricultural forest can be more fully returned to a site. A dense needle carpet and frequent levels of Schreber's and shaggy mosses are the most distinguishing features of the forest floor, where low light availability generally results in reduced shrub and herbaceous cover and diversity. Extensive fruiting of mycorrhizal mushrooms, including chanterelle and boletes, may occur in late summer and fall. The presence of old rock walls and foundations, apple trees and nearby fields and active farms makes this particularly unique and productive habitat for a number of wildlife species.
|1a. White spruce and/or tamarack dominant||2|
|1b. White spruce and/or tamarack not dominant||3|
|2a. Tamarack absent to scattered||OF1 White spruce / Aster – Goldenrod / Shaggy moss|
|2b. Tamarack abundant to dominant||
OF2 Tamarack / Speckled alder / Rough goldenrod / Shaggy moss
|3a. White pine dominant||OF3 White pine – Balsam fir / Shinleaf – Pine-sap|
|3b. White pine not dominant||4|
|4a. Balsam fir dominant||OF4 Balsam fir – White spruce / Evergreen wood fern – Wood aster|
|4b. Aspen dominant||OF5 Trembling aspen – Grey birch / Rough goldenrod – Strawberry|