Hi Phanith, it would depend very much on the type of NTFP. I know that in some cases overharvesting of seeds can reduce the regeneration of the plant so this is a negative feedback. I have also heard of overharvesting of fungi leading to reduction in population which could also have a negative impact on the ecosystem. In terms of positive impacts I suspect that for NTFPs that provide a good income that this would induce local people to protect the resource. Unfortunately the majority of NTFPs used by forest peoples are of low value or even resources of last resort.

Dear Phanith,

Please have a look to:

http://dx.doi.org/10.17348/era.12.0.561-570

Dear Phanith

NTFPs supports humans in variety of ways ranging from health care to nutrition to some non-consumable items such as decorative materials to durable. Moreover, tribal generally collect these produce and receive income out of selling the produce. You can use direct and indirect economic valuation method to extract the economic value of the produce. Several researchers has dealt on the issue. Yes, fully agree, collection of primary data for NTFP is tedious task.

Regards

Dear Uwe and Albert, thank you very much for your suggestion. That is really helpful to read your answers. @Dear Berty: How are you? I am thinking the same as yours. Income from NTFPs probably an incentive for the community to conserve the forest. We probably can calculate this value from the conservation costs. Thank you very much for your answer. @Dear Rajiv: Thank you very much for your answer. I am writing one article very similar to what you are suggesting. That is really interesting. However, I am finding the value which beyond the consumptive value its' self. Best Regards. Phanith. 

@Dear Rajendra: Thank you very much for your answer. Your introduced concept place-based ecosystem services is really interesting. I am curious to study more about this. 

Hi Phanith,

This is tough question, which I thought about lots during my MSc.Here's my thoughts.

NTFP fit best into the ecosystem services (ES) category of provisioning ES. However, I strongly agree with you that many NTFP have values that go well beyond their consumptive role and economic value.

The most direct way for monetary evaluation would be to first do biophysical estimation of NTFP harvest (eg, edible fruits per ha), then multiply that by a market price. 

Keep in mind that it is now only a relatively small subset of the total ES studies that concern with economic valuation. Most quantification studies focus only on biophysical measurements (eg, relative abundance, weight berries, probability of presence, etc.) and this can be perfectly useful depending on the goals of the research.  

For example, I've recently published an article that quantifies multiple forest ecosystem services across different forest types and age classes. In this article we look at some typical NTFP such as abundance of edible foods (relative abundance) and yield of merchantable floral greenery products (Kg/ ha). For these we could have probably taken it a step further to estimate economic value. But  other NTFP we looked at (large cedar for aboriginal carvings) were primarily important for their immense cultural value to the local indigenous people.

Sutherland, Ira J., Sarah E. Gergel, and Elena M. Bennett. "Seeing the forest for its multiple ecosystem services: Indicators for cultural services in heterogeneous forests." Ecological Indicators 71 (2016): 123-133.

To sum my thoughts up, I think that it may be very difficult to reduce many NTFP's to a meaningful $$$ figure. For others it may be more feasible. There is a lot to read into if you are interested in the diverse (non-economic) values of ES. I would start with the work of Kai Chan, and other work on 'cultural ecosystem services.'

Dear Phanith,

I have recently started working with acai (Euterpe oleracea) in the Amazon estuary. The palm, which is native to the flooded forests of this region is an example of a NFTP that is now a driver of ecosystem service loss, as well as a provider (provisioning service = palm fruits). Acai was initially considered as a means to conserve forest habitats, but its popularity and high value of harvested fruits have lead to a rapid 'acaification' of the forest habitats, which has had strong negative impacts on diversity, function, and ecological integrity of local forests. I hope this provides a good cautionary tale about how NTFP do not always bring about positive consequences for biodiversity. You can read more about this in the article of my colleague, Madson Frietas (see link below).

Article Floristic impoverishment of Amazonian floodplain forests man...

@Dear Ira, thank you very much for your contribution. That is really much helpful for my current research and publications. According to my previous technical report published by WWF, I selected six NTFPs to assess the economic value by using benefits transfer function. However, this research, I added two more commodities for the analysis. My thoughts are open into doubts because their importance was not even equal to the farming or logging, so the local government does not integrate NTFPs in their development agenda. As the results, the deforestation has occurred sharply. In a national conference, governor and central gov asked me, prove me if NTFPs have value beyond household economic. That is the reason leading to look up the value of non-economic as you mentioned. However, thank you very much, and thanks for your journal. I will read them in detail. 

Dear Alistair, 

First of all, thank you very much for your answer. That is really useful. Over-exploitation or NTFPs cultivation always impact negatively more or less to the ecosystem. The ideas from ecological costs from NTFPs extraction is appreciated. Thank you very much, especially to the journal. 

Hi again, 

I just want to emphasize a bit more here that the cultural value perception of many NTFP may far exceed local peoples perceptions of the utilitarian or economic value of NTFP's/

This video, which accompanies my previously mentioned paper, makes a strong case that some NTFP have extremely high cultural value for indigenous people. The tree species western red-cedar is intrinsic to the way of life, worldview and identity of the Nuch-a-nulth people https://vimeo.com/110663633 

Also, see another point made by Saarikoski et al 2015 and Chan et al. 2012, which is that the presence of edible foods in the forest enhance the cultural experience of visiting the forest. many ecosystem services combine (clean air, noise reduction, wild edible foods) to provide the visitor experience - a memorable and revitilizaing visit to the forest. 

Saarikoski, Heli, et al. "Exploring operational ecosystem service definitions: The case of boreal forests." Ecosystem Services 14 (2015): 144-157.

Chan, Kai MA, et al. "Where are cultural and social in ecosystem services? A framework for constructive engagement." BioScience 62.8 (2012): 744-756.