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Alternative Regeneration Standards Knowledge Gaps & Research Needs Presented to: Foothills Growth and Yield Association Technical Meeting – 5 March 2008

Presented by: Richard Briand – Hinton Wood Products

What do we know? • Donald Rumsfeld: – “…as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns - the ones we don't know we don't know.“

Performance survey • What do stands look like at age 14 years? – What proportion of the stems are above BH? – What proportion of the stems are below BH? How will these trees develop? Do they contribute to harvest age yield? How are they modelled in growth models? If they are at all. – Can we reasonably model ingress? Should we?

How important are trees <1.3m at age 14?

Treatment response • How will treated stands develop? – Post thinning development – Post herbicide development – Pose tending development – Deciduous stems growing “under” conifer. Are there any growth models that can reasonably predict this? Should we just ignore these?

Diameter • Diameters in young stands are difficult to assess (within reasonable error limits). • What should we measure to assess the success of management/EFM treatments? If it’s diameter….which diameter – DBH? DSH? D80? • If we can’t reliably assess diameter, will we have to wait until after the performance survey to show the value of the treatments?

Density • Some variables are not normally distributed, do we need to compile these differently?

% plots

Trees / Plot

Height • How useful is sampling top height in young stands? If it’s not useful, what’s better? • Are we measuring site index when we assess top height in performance surveys? No…but we are assessing a consistent measure of height…a “Height Index” – how does this relate to site index? • Should we measure average height? • Should we measure the tallest trees (max ht)?

Height/Diameter Distributions • •

• • • •

Can we quantify the height and diameter distributions in “typical” young regenerating stands? Can we quantify the height and diameter distributions in “typical” natural stands? Our current growth models are built on these kinds of stands. When we use these models, we must understand what these differences are in order to interpret model results properly. How do these distributions change over time? Could we incorporate these distributions into our sampling protocols? Could we make reasonable assumptions of the distribution of stems below a measurement threshold? How much do the “atypical” stands vary from the typical? What percentage of our stands are “typical”?

Height Class Distribution

% of stems






2.8- 3.3+ 3.3

Height Class Distribution Can we â&#x20AC;&#x153;assumeâ&#x20AC;? these trees are present?



If we measure these?




2.8- 3.3+ 3.3

Height Class Distribution But we have to know this first!






2.8- 3.3+ 3.3


• ….actually mixed CONIFERS! • Many silviculture folks are planting pine and spruce trees in regenerating blocks. • Can we model development of these kinds of stands?


Shrubs • Are shrubs more prevalent in managed vs. natural stands? • Are they beneficial? • At what levels do they compete with commercial species development? If any? • Do we need to introduce this into growth models?

Regeneration and Growth Phases

Establish -ment



Growth Regeneration Rotation

Establishment  Performance • We need to link stand conditions in the establishment phase with those in the performance phase, but… – What are the key variables? – Is it really too chaotic to model, or have we just assumed it is? – If we have an objective of achieving a certain yield from a regenerating cutblock – how will our silviculture foresters determine what they should do at age 0?

Growth & Yield Programs • We are collecting a tremendous amount of data at performance survey – intended to provide an estimate of yield. • How does ARS fit within an overall growth and yield strategy for an FMA?

Growth & Yield Programs 300

When does a new inventory take over? 250

PSP Program -> Regenerated Stand PSP’s







Volume per ha (m )


How do we incorporate ARS forecasts into the G&Y program? - Empirical yield curves - Model derived yield curves

0 0




40 Stand age (years)





Advanced Growth • Understorey protection (Sw under Aw): mixtures of advanced growth and seedlings. How should we assess these cutblocks? Can we model the development of these stands? Do we even have the data necessary to build the models? • Same question for pine stands with understories after MPB attack.

MPB • Will pine regenerate as well after MPB attack? • Not so much an ARS question – but a pine regeneration question. • What potential problems should we expect? • Are we going to have to plant more? Plant what species? • How will mixed species stands develop?


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