Forest Vegetation types - Successional Development


         

Succession, as defined by Odum (1971), is an orderly process of community development that involves changes in species structure and community processes with time; it is reasonably directional and, therefore, predictable.

Successional development generally proceeds through a number of distinct stages (e.g. early, middle, late) that replace one another in a predictable sequence and which culminates in a relatively stable and self-perpetuating community condition called a climax. Climax communities are not static, but are subject to gradual long-term renewal, maintaining themselves (more or less) until stand-level disturbance causes a return to an earlier successional stage.

A climatic (or zonal) climax results when a forest community reflects regional climate norms and is not unduly affected by local extremes in site conditions. Although Nova Scotia is divided into nine climate-based ecoregions (Neily et al. 2005), for FEC purposes the province can be effectively represented by two ELC groups, referred to as Acadian and Maritime Boreal (See Forest Ecosystem Classification for Nova Scotia: Part III Ecosites (2010) for more details).

In the Acadian group, zonal climax forests are dominated by species such as hemlock, red spruce, sugar maple and beech. In the Maritime Boreal group, climax species include white spruce, balsam fir, red maple and white birch.

An edaphic climax results when a forest community cannot progress to the climatic climax due to local extremes in site conditions (e.g. low nutrient sites, dry sites, wet sites and floodplain sites). Species associated with these sites include black spruce, tamarack, red maple, pine and white ash.

Figures 3 to 7 summarize possible successional links between VTs in the Spruce Hemlock (SH), Spruce Pine (SP), Tolerant Hardwood (TH), Intolerant Hardwood (IH) and Mixedwood (MW) forest groups — the main forest groups found in the province.

Information contained in Figures 3 to 7 can be used to aid forest management planning; however, users are reminded that many variables can (and do) affect stand successional dynamics including: (i) the type and size of disturbance, (ii) the frequency and severity of disturbance, (iii) age class and structure at time of disturbance, (iv) presence / absence of advanced regeneration, and (iv) presence / absence of seed sources, etc. As a result, the successional links shown in Figures 3 to 7 should be considered a guide to what is possible, not a hard and fast rule or prescription.

Figure 3. Spruce Hemlock (SH) Forest Group — Successional Links

  Early Middle Late
SH1 IH3, IH4, IH6, MW4, MW5 MW2, SH5, SH6, SH8 MW3, SH1, SH2, SH3
SH2 IH4, IH6, MW4, MW5 MW2, SH5, SH6, SH8 SH1, SH2, SH3
SH3 IH3, IH4, IH5, IH6, MW4, MW5 MW2, SH5, SH6, SH7, SH8 SH1, SH2, SH3
SH4 IH1, IH2, IH4, IH6, MW4, MW5 MW2, SH5, SH8, SH9 SH4
SH5 IH3, IH4, IH5, IH6, MW4, MW5 MW2, SH5, SH7, SH8 MW1, MW3, SH1, SH2, SH3, SH4
SH6 IH3, IH4, IH5, IH6, MW4, MW5 MW2, SH6, SH7, SH8 MW1, MW3, SH1, SH2, SH3
SH7 IH3, IH4, IH5, IH6, MW4 MW2, SH5, SH6, SH7, SH8 MW1, MW3, SH3
SH8 IH3, IH4, IH5, IH6, MW5 SH5, SH6, SH7, SH8, SH10 MW1, MW3, SH1, SH2, SH3, SH4
SH9 IH4, IH6 SH9, SP4 SH4, SP5
SH10 IH4, IH6, MW4, MW5 SH8, SH10, TH7 MW1, MW3, TH8


Figure 4. Spruce Pine (SP) Forest Group — Successional Links

  Early Middle Late
SP1 SP1 SP2, SP3, SP4 SP5
SP2 SP1, SP2 SP3, SP4 SP5
SP3 SP1, SP2 SP3, SP4 SP5
SP4 SH9, SP1, SP2, SP8, SP9, SP10 IH2, SP3, SP4, SP6 SP5
SP5 SH9, SP1, SP2, SP8, SP10 SP3, SP4, SP6 SP5
SP6 IH1, SP8, SP10 SP4, SP6 SP5
SP7 SP7 SP7 SP7
SP8 SP8 SP4, SP6 SP5, SP9
SP9 IH1, SP8 IH2, SP4 SP9
SP10 SP10 SP4, SP6 SP5


Figure 5. Intolerant Hardwood (IH) Forest Group — Successional Links

  Early Middle Late
IH1 SP1 SP2, SP3, SP4 SP5
IH2 SP1, SP2 SP3, SP4 SP5
IH3 SP1, SP2 SP3, SP4 SP5
IH4 SH9, SP1, SP2, SP8, SP9, SP10 IH2, SP3, SP4, SP6 SP5
IH5 SH9, SP1, SP2, SP8, SP10 SP3, SP4, SP6 SP5
IH6 IH1, SP8, SP10 SP4, SP6 SP5
IH7 SP7 SP7 SP7


Figure 6. Tolerant Hardwood (TH) Forest Group — Successional Links

  Early Middle Late
TH1 IH3, IH5, IH6 IH7, TH6, TH7 TH1, TH8
TH2 IH3, IH5, IH6 IH7, TH6, TH7 TH2, TH8
TH3 IH3, IH5 IH7 TH3
TH4 IH3, IH5   TH4
TH5   IH7 TH1, TH2, TH5
TH6 IH3, IH4, IH6 IH7 TH1, TH2, TH6
TH7 MW4, MW5 IH7, SH10, TH7 MW1, MW3, TH1, TH2
TH8 IH3, IH4, IH5, IH6 IH7, SH10 TH1, TH2, TH8


Figure 7. Mixedwood (MW) Forest Group — Successional Links

  Early Middle Late
MW1 IH3, IH4, IH5, IH6, MW4, MW5, SH8 IH7, MW2, SH5, SH6, SH7, SH10, TH7 MW1, MW3
MW2 IH3, IH4, IH6, MW4, MW5 MW2, SH5, SH6, SH7 MW1, MW3, SH1, SH2, SH3, SH4
MW3 IH3, IH4, IH5, IH6, MW4, MW5, SH8 MW2, SH5, SH6, SH7, SH10, TH7 MW1, MW3, SH1
MW4 IH4, IH5 MW2, MW4, SH5, SH6, SH7, SH10, TH7 MW1, MW3, SH1, SH2, SH3, SH4
MW5 IH5, MW5 MW2, SH5, SH6, SH8, SH10, TH7 MW1, MW3, SH1, SH2, SH3, SH4


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