i suppose more than 50% Advance growth represents healthy forests.

Thank you, do do you know of literature on this?

I think you are comparing within a single species, so it would not be unusual to have low numbers of seedlings or saplings under the parent tree(s) as some species produce chemicals that suppress germination of their own species seeds.  There are also issues of high densities creating ideal conditions for pathogens, attracting herbivores etc.  Herbivory may cause a shift in forest composition e.g. I recall a presentation by Peter Wardle in which he noted an apparent suppression of beech (Fuscospora)  in favour of podocarp spp. on forest margins  by cattle in the Arawata Valley.

In a sense I am saying it all depends on the species and how it fits into the overall picture.  In terms of what I know of NZ forest, there are some long-lived seral species that disappear over time and won’t occupy a small forest gap e.g. kanuka, and it is not often that you would see saplings of any species growing up directly under the same species even in the monotypic beech forest, saplings are mostly in gaps or under senescent trees.  I would expect composition to change to some extent over time but the overall pattern for a landform across an extensive area to stay much the same and that that would have little to do with how many seedlings can be seen (so long as there are some).

And sorry I don’t have references right now but Dave K. has course work on/around this topic.

yes. in the manipulation forest and the destroyed forest due to cattle grazing or due to poor soil, the number of seedling are increased. because the ability of forest for regeneration is increased. as a result the number of saplings are increase and all of this cases affected to the future of forest and forest composition will be changed

see the attached article for data on the seedling, sapling, tree proportion in native tropical forest versus an adjacent restored forest.

Article Does forest restoration using taungya foster tree species di...

http://www.scielo.br/pdf/rbb/v28n4/30367.pdf

I am happy to hear, Hazel, you find my our paper with seedling, sapling and tree counts from the tropics helpful. From my observations in coniferous montane forest (e.g. Baluchistan, California) I would say that a mismatch between mature trees and recruitment saplings is not uncommon. Recruitment of canopy trees could be an episodic event (once in a century?) rather  than a continuous process. Fires, extreme weather events, land abandonment the potential drivers. An example after a rare fire event in the montane belt of the Apennines is attached

Article From monospecific to mixed forest after fire?: An early fore...

Good regeneration could be stated where Seedling>Sapling>Adult, where Fair regeneration = Seedlings Adults.. In forest ecosystems the mortality rate of seedlings is often high followed by that of saplings. Hence, the total sustainable regeneration needs to be calculated. Recruitment is influenced by upper canopy and aspect as well along with other factors.  ratioSo it is better to take all these parameters into account.

A value for adult:sapling ratio 1 or more than 1 can only be treated as a healthy recruitment (quantitatively).

I agree with Graeme that it is highly species specific. In Hawaiian tropical forests the two dominant canopy species (Acacia koa and Metrosideros polymorpha) have entirely different ratios.  Koa trees sprout not too often, grow into saplings virtually everytime, but then often die at the sapling stage.  Ohia on the other hand produce a remarkable amount of seedlings that very rarely make it to the sapling stage, but the saplings virtually will always survive into the tree stage.  Both represent healthy recruitment, even though the ratio of saplings to trees are entirely different because of the different recruitment strategies of the two trees.  Using Gautamʻs framework then the healthy recruitment for the two canopy trees looks like:

Koa - Seedling=Saplings>>Adult

Ohia - Seelings>>>SaplingsSaplings>Adult, but again shows  variation between species.

I am also looking for a healthy ratio of regeneration rather than gneral statement such

Seedling>Sapling>Mature trees. Any new papers in this regard?

In a tropical forest with young populations, the health is determined by the fact that the number of seedlings is greater than saplings and is further greater than adult populations. Increase in number of young populations indicate the healthy nature of a tropical forest ecosystem. However, regenerative capacity can be determined from class-wise classification of seedlings, saplings and adult trees with respect to their girth size. Natural regeneration utilizes reproductive capacity of the parent stand for the emergence of a new forest generation, which comes

to existence either from the fallen seeds, from the coppice shoots or from the root suckers. In the commercial forest, natural regeneration is connected with the purposeful activities of forest managers. The forester intervenes in the forest regeneration in line with the site requirements, requirements of the regenerated tree species and other factors – e.g. by soil preparation (soil scarification to facilitate germination of seeds and establishment of seedlings), weed control, opening up of the parent stand (by cutting some trees in order to increase light treat in lower forest storeys) etc.

Artificial regeneration is a method of intentional activity of the forest

manager. New stand comes to existence through the planting of seedlings

and transplants raised in forest nurseries or through the sowing of seeds and

fruits.