Update Allometric Models

Technical Note for Journal of Nepal Foresters’ Association, 2011 issue:

Update Allometric Models

Amulya Ratna Tuladhar¹

This technical note deals with an urgent and doable opportunity to improve the science for many of Nepal’s forestry and environmental policy needs. For instance, the uncertainties of carbon sequestration estimates of Nepal’s forests can be greatly reduced for more robust policy response to climate change effects (BJ editorial, 2009).

Most of the estimates of carbon sequestration by Nepalese forests have been derived from the empirical measurements of the diameter at breast height (DBH) of some standing trees (Baral et al., 2009; Tewary and Karky, 2007). From this primary DBH variable measured, secondary estimates of other variables of interest are derived from allometric models and tables. These derivative estimates such as carbon percentage, biomass, volume or crown areas come from regression models of tree allometry which have been developed through destructive sampling and measurement of tree parts such as roots, stem, branches, crown area (Brown, 2002; Sapkota and Meilby, 2009). Such empirically developed allometric models are few and far between, from ones developed in Indonesia (Basuki, et al., 2009; Chave, et al., 2005) to ones developed from Nepal over a decade ago (Sharma and Pukkala, 1990).

One reason such models are rare is because it is very difficult to cut trees for research purposes, under scientifically controlled circumstances and measure parts in a systematic way to develop models for each species, area and management scenario. Consequently, most estimates of large-scale forest measures have to depend on whatever allometric models are available. Therefore, the choice and application of these models have to navigate treacherous ecological assumptions to map out the applicability of such research for policy conclusions.

¹Professor of Environmental Sciences, amulya_tuladhar@yahoo.com

To illustrate such limitations, this technical note analyzes the ecological limitations of one of the finer research articles of this issue. Shah (2011) in this issue has used an innovative variable, the crown area remotely sensed by GeoEye high-resolution satellite imagery, to model carbon sequestration of Nepalese forests. To do so, he has used an intermediary allometric model to link crown area to dbh and then from dbh to biomass estimates and carbon sequestration models. These allometric models have been drawn from Indonesia (Basuki, et al., 2009) because ‘they share same climate and species family as Nepali trees and because allometric models for Nepal was not available to him’.

“Tropical Sal” of Chitwan.

These claims deserve scrutiny. Do the Sal (Shorea robusta) trees of Chitwan share ecological and botanical characteristics of Indonesian dipterocarps, which justifies use of allometric models, developed there for Nepal?

Chitwan Sal is deciduous, although occurring in tropical zone according to Jackson (1994) following ecological classifications by Dobremez and Stainton whereas the dipterocarp of Indonesia are evergreen rainforests (McNight and Hess, 2000). The key ecological difference is the continual growth of cambium in tropical evergreen forests which have no separate seasons (Goudie, 1993) versus the differentiated seasonal growth of cambium due the presence of a dry season in Chitwan (Jackson, 1994b). Because of such dry season, Chitwan Sal sheds most of its leaves in winter and spring without going completely naked. This ecological habit has implications on the allocation of tree growth mass on its roots, foliage, branch and stem wood that would make the application of Indonesian allometric models of dipterocarps on Nepali Sal questionable at best.

“Old” Allometric Models

Shah (2011) mentions that allometric models for Nepalese Sal were unavailable to him but a number of carbon sequestration studies in Nepal have used allometric models developed by Forest Ministry some time ago (Sharma and Pukkala, 1990). These models were developed at a time when carbon sequestration interest did not exist and the most these models tried to develop were estimates of foliage and branch wood to get estimates of fodder and fuelwood biomass to support livelihood policy (FORESC, 1996; HMG/Nepal, 2000). Generally, the management objectives for Sal in Government natural forests was for timber where the harvest age, called rotation, was between 80 to 120 years (Parkash and Khanna, 1979; NFI/FINIDA. 1999). These models become inadequate for estimating forest goods such as fuelwood, fodder, NTFP and for ecological services such as water flow or carbon sequestration. Therefore, a new updated series of allometric models have to be developed for the changed context, using carefully planned scientific control and destructive sampling of tree parts of different trees of Nepal under different management scenarios. Such a task can be undertaken by Forest Ministry, Forestry Schools or Research Institutions provided a clear mandate be given for tree cutting for research to protect this activity from being accused as illegitimate logging for money.

Reference:

Baral, S.K., R.Malla, S.Ranabhat. 2009. Aboveground carbon stock assessment in different forest types of Nepal. Banko Janakari, 19(2):10-14.

BJ editorial. 2009. Forest Carbon Inventory (editorial). Banko Janakari, 20 (2): 1-2.

Basuki, T. M., van Laake, P. E., Skidmore, A. K. & Hussin, Y. A. 2009. Allometric equations for estimating the above-ground biomass in tropical lowland Dipterocarp forests. Forest Ecology and Management, 257(8), 1684-1694.

Brown, S. 2002. Measuring carbon in forests: current status and future challenges. Environmental Pollution, 116(3), 363-372.

Chave, J., Andalo, C. & Brown, S. 2005. Tree allometry and improved estimation of carbon stocks and balance in tropical forests. Oecologia, 145(1), 87-99.

FORESC, 1996. Biomass table of ten preferred species by forest users' group in the hills of Nepal. Forest Research and Survey Centre (FORESC), Ministry of Forests and Soil Conservation, Kathmandu.

Goudie, Andrew. 1993. The Nature of the Environment. Third Edition. Blackwell.

HMG/Nepal, 2000. Biomass and volume tables with species description for Community forest management. TISC technical paper series no. 101 (90pp)

Jackson, J. K. 1994. Manual of Afforestation in Nepal, Volume 2. Second Edition. Forest Research and Survey Center, Nepal.

Jackson, J. K. 1994b. Manual of Afforestation in Nepal, Volume 1. Second Edition. Forest Research and Survey Center, Nepal.

Parkash, Ram and L. S. Khanna. 1979. Theory and Practice of Silvicultural Systems. Periodical Expert Book Agency. Delhi-110032.

McNight, Tom L. and Darrel Hess. 2000. Physical Geography. Sixth Edition. Prentice Hall.

NFI/FINIDA. 1999. National forest inventory. Department of forest research and survey. Ministry of forest and soil conservation, HMGN/ FINIDA, Report No.74, pp. 48.

Sapkota, Prativa and Henrik Meilby. 2009. Modelling the growth of Sal (Shorea robusta Gaertn. f.) using growth ring measurements. Banko Janakari, Vol. 19(2):25-32

Shah, Shyam K. 2011. Use of very high-resolution imagery for estimation of above ground carbon stock of stand-alone trees of dominant species of subtropical forest. The Nepal Journal of Forestry, Vol XIV(1):3-22.

Sharma, E.R. and Pukkala, T. 1990. Volume and biomass prediction equations of forest trees of Nepal. Forest survey and statistical division. Ministry of forest and soil conservation, Kathmandu, Nepal

Tewary, Ashish and Bhaskar Singh Karky. 2007. Carbon Measurement Methodology and Results. IN Kamal Banskota, Bhaskar Singh Karky and Margaret Skutsch (edt.) Reducing Carbon Emissions through Community-Managed Forests in the Himalaya. ICIMOD. Nepal.

Amulya's Published Articles on Population, Development & Environment

CBS LATEST: POPULATION NO LONGER A DEVELOPMENT PROBLEM FOR NEPAL?

Wednesday, September 28, 2011

CBS LATEST: POPULATION NO LONGER A DEVELOPMENT PROBLEM FOR NEPAL?

AMULYA RATNA TULADHAR

26.6 million, instead of 28.5 million expected, is the latest Central Bureau of Statistics (CBS) preliminary estimate for Nepal’s 2011 census! With 2 million people less than predicted, will population no longer be a development problem for Nepal?

Yes and No. The answer merits nuancing.

YES:

Yes, it would no longer be a development problem; this could be argued 3 ways:

FIRST, population numbers have been a big specter for most of Nepal’s modern era beginning from 1950, when it started to open to the benefits of development from the outside world. Nepal moved rapidly from about 8 million people in 1950s to nearly 27 million in 2011, over a triple. Fears of Malthusian doom rose in the 1970s and materialized by the 1980s when Nepal turned from a food surplus to a food deficit country. Will the increase in population numbers negate the benefits from development has been an anxiety of Nepalese. It looks like population now has some chance of stabilizing i.e. not grow relentlessly over the coming century. The latest declines in expected population numbers hints this.

SECOND, population numbers that threatened to double at shorter and shorter intervals, from 60 yrs in the beginning of 1950s to 26 years in 1980s, have now slowed to longer periods, 51 yrs for the current growth rate of 1.4 %, a good reduction from 2.25% in the earlier decade. Many demographers had observed a slow decline in mortality from 1911 to 1961 and fertility declines from 1961 to1996, with the average number of children per Nepali woman (Total Fertility Rate, TFR) declining from 6 to 5 between 1961 to 1981 and now to 2.7 in 2011, according to the National Demographic Health Survey.

THIRD, demographers like Pitamber Sharma now confirm that Nepal’s population has moved to Stage III of the demographic transition observed in many European countries over the last 2 centuries and which is theorized to explain population change in the world and Nepal. According to the demographic transition model, if correct, the population is like to stabilize in the near future. Demographer Shyam Thapa had studied 4 different scenarios of declines in fertility rates, leading to 46 to 100 million by 2100. The current 2011 estimate of 26.6 million suggests that Nepal is demonstrating the faster fertility declines rates observed in Asian countries and so our stabilizing population would likely be closer to 46 million than 100 million and that would be achieved around 2050 than 2100. So, is that good news, that we would not have runaway population numbers?

NO:

Even if we can expect a capping of population over the coming century we could still have at least 3 types of development problems in Nepal as discussed below:

FIRST, Until, we reach a cap, population numbers will still grow due to the large fraction of young people who are yet to reach their fertile periods of ages 15-45. This is variously called population bulge, or population momentum. Such increase in population numbers, to at least double the current 26.6 million, would mean the net increase in demands for services. Given than even in 2011, 83% of the population are still rural, such demands would be made upon rural and natural resource environments. Such a trend is confirmed by the continued growth in population density of mountains and hills despite increasing outmigration from these regions. As a result both food insecurity and livelihoods vulnerabilities are expected to increase.

SECOND, Some of this increase in population and their demands for employment have been absorbed by outmigration and remittance economy, which has accelerated over the last decade. The National Living Standards Survey III of 6000 households in 2011 suggested that over half of Nepalese households (56%) had at least one member absent or remittance economy. The preliminary 2011 census results suggests that 2 million Nepalese are absent, presumably for remittance economy. Our development economy has not grown enough to support these 2 million who have had to outmigrate.

THIRD, Can Nepal continue to depend on outmigration and remittance to solve this population bulge over the coming century? It is not all that bad. USA and colonial countries served as outlets for Europe’s growing population too. The economies of India and China and other countries better off than Nepal might continue to demand Nepal’s human resources for the foreseeable decades, despite some danger of economic and political downturns. The remittance economy, of late, has been credited with bringing more development in the lives of ordinary Nepalese than 50 years of nation-state led trickle down “development” because at even a modest average of Rs 9000 a year per household, the remittance income goes directly to the households, yielding a demonstrable payoff in nutrition, health, and literacy rates returns that enhance their measurable human development indices.

INSIDIOUS EFFECTS

Despite the documented positive effects of outmigration and remittance economy on Nepal’s development, the following insidious effects have to be monitored:

A) The exposure to outside ideas and higher income increases the aspirations of the outmigration households. We can expect a faster and larger scale diversion from nature-based economy to non-nature based economy (e.g. a switch from forest fuelwood to imported gas). This will relieve the pressures of growing population on the natural environment.

B) The outmigration households will also demand faster and better services from the State from material services to political and social rights so there would be great pressures for social change; however, because of the extended duration of their residency outside the country, the social and human capital necessary to build institutions to deliver such services of change may not develop fast enough, so the possibility for conflicts increase.

C) Despite a significant chunk of population outmigrating, in 2011, such as the hill districts of West Nepal (Parbat, Gulmi, Arghakhanchi, Pyuthan etc) witnessing a population decline, we still have a recalcitrant residual population of the poorest of the poor, weakest of the weak, the landless, the indigenous, and the low caste that have very little economic, social other resources to escape the dire situation of their Nepalese landscape. These social groups are faced with the new and grave threat of climate change effects that are likely to create negative synergies to create non-linear, catastrophic, environmental and social disasters and surprises such as Nara village massacre for Yarsa Gumba, the loss of biodiversity resources from Eastern Himalayan hotspots, the exacerbation of glacier melts and GLOFs, and environmental refugees escaping water shortages, to name a few.

CONCLUSION:

The latest CBS census results raises the hopes of a capping population numbers relieving pressures on Nepal’s development but the insidious dangers of outmigration and remittance economy continue to exist in the foreseeable future where Nepal’s population is still likely to double before the century is over.

Professor Amulya Tuladhar teaches graduate level Population and Development in Nepal.

Please see amulyatuladhar.blogspot.com and communicate with tuladharamulya@gmail.com

POPULATION AND ENVIRONMENT OUTSIDE THE BOX

Population and Development Outside the Box

Amulya Ratna Tuladhar, 2011

(published in toto in the republica, july 17, 2011)

One hundred years of counting Nepalese, this year 2011, is a good time to do some outside the box thinking on population and development. What are ways of broadening the discourse of business as usual categories that keep yielding the same old, same old understanding and solutions that most of us are exasperated about? What follows is a sample of such an effort in graduate course of population and development; for details readers are invited to visit the blogsite http://amulyaratna.blogspot.com/ for DEVS 504.

Nepal’s population increased nearly 4 times in 90 years since the first census in 1911 to the last census in 2011. Before this census, indirect reconstructions had our country’s population around 3 million around Prithvi Narayan’s time in 1768.

What will be our country’s population in the future, the next 100 years? 100 million? 60 million? Or 40 million? Depending on how we handle the rate of our fertility decline, says demographers Shyam Thapa and his colleagues in 2001.

The demographic transition from high birth and high death rates to low birth and death rates, observed in Europe over the last 200 years seems to be happening at a much faster rate in Nepal. A stabilizing population seems to be in sight contrary to the Malthusian doom we are currently facing with population rates exceeding our food production rate.

Will the population numbers and rate outpace our development and national aspirations to have a better life? Contrary to our frustrations that India and China who were as destitute Third World nations like Nepal 60 years are now chugging ahead while we seem to be stuck behind? Right?

Wrong! The Human Development Index, a composite of Wealth, Health and Literacy shows that we have made almost 100% progress over the last 30 years from 0.210 to 0.428; agreed there is a lot disparity over space, time, class, gender, castes etc and some even have reservations over the methodology and assumptions of such a measure.

One such glaring inadequacy is the non inclusion of Environment in this index. “Are we better off now than we were 30 years ago, in terms of environment?” we can ask the Reaganesque question.

The World Bank in 2007 asked this same question in their Country Environmental Analysis of Nepal. And,… the Bank conceded that environmental costs of getting rich has been high, up to 3.5% of GDP in higher health costs alone and this is likely to be higher since up to 50% of the national economy is directly or indirectly linked to natural resources of the environment.

How do we protect the environment and reduce poverty is the central policy question of the Poverty-Environment Initiative (PEI) Nepal framework for 2010, developed by the National Planning Commission, the Ministry of Local Development and the UNDP Nepal and UNEP. This Initiative has tried to integrate pro-poor climate and environmental concerns for sustainable development. Have we not heard that before?

Conflict with environment is an emerging issue discussed in a paper by Asian Development Bank and ICIMOD in 2006. Widespread conflicts over a range of natural resources such as forests, land and water have been noted and these have spread to urban environment too. A well developed means of environmental conflict resolution does not seem to exist.

Environmental conflict is thought to be driven by increased scarcity of environmental resources. Some relatively successful examples of environmental conflict management include Nepal’s community forestry but there are many unsuccessful examples as in urban environmental issues where even the Supreme Court decisions on the Government bodies to adhere to environmental laws of the land are routinely ignored.

Theoretical reasons for such conflict may be rooted in the oxymoron juxtaposition of sustainable development as two antagonistic ideologies: ‘sustainability’ originally coming from World Conservation Strategy, 1980, developed by global ecology bodies such as IUCN, WWF and UNEP to mean limits due to ecology while the ‘sustainability” from Brundlandt Report 1987 mean limitless economic growth to meet the needs of human generations ad infinitum. Conflict is therefore the necessary essence of sustainable development maintains Redclift in his 2005 paper.

Environmental degradation is even alleged to be a hitherto unacknowledged “ultimate cause of Maoist rebellion” in Nepal, asserts Bhurtel and Ali in their 2003 research paper. This is in stark contrast to a plethora of social, political and economic explanation we have heard so far.

The role of State as part of the problem in the population and development issues of Nepal is an outside the box thinking. No longer is it accepted that the State is a secular conduit of development or even an agent of positive change. This discourse deserves our serious attention.

A theoretical paper on the transformation of the Nepalese State by David Gellner in 2002 takes us from pre-State Nepal through the centralized monolithic State to the contested idea of State. Instances of the variegated shape, reach and power of the Nepalese State with respect to environmental programs is documented by Ben Campbell.

In 1989 when I visited Kandebas ridgeline boundary between Gulmi and Baglung as a part of Lokta stock assessment for UNESCO, villagers there were still practicing the traditional Mana-Pathi community management of forests although Nepal was theoretically under the uniform management of the Private Forest Nationalization Act 1957.

It is clear the State is NOT the exclusive player in population and development in Nepal. This is a theme that has been intellectually explored by political ecologists such as Piers Blaikie and Harold Brookfield, 1987, in their landmark Land Degradation and Society. Here, the Himalayan land degradation is presented as a crisis of explanation rather than a crisis of ecology; an effect cascading from international political economy all the way to the land manager farmer in their interaction with the local environment.

The intellectual and theoretical boundaries of political ecology have been pushed to Liberation Ecology by Michael Watts and Richard Peet, 2004. Here the State has been de_essentialized as a contested agency of social and political movements dealing with social equity and environmental livelihoods such as Chipko Andolan. The contestation has broadened from material means of production such as land, labor to non-material knowledge and discourse on how power is created, negotiated, and transformed into material change in population and development.

An example of how discourse, like the tale of Emperor’s New Clothes, can prohibit certain powers (Only the wise can see the Emperor’s fantastic naked costume) is illustrated in contrasting development discourses on male migration in Nepal by Jeevan Sharma in 2008. Here, he demonstrates how the dominant development discourse paints migration as an activity to be ashamed of, while an alternative discourse paints migration as a romantic, adventurous activity to be proud of.

One of the dominant discourses relevant to Nepal is The Himalayan Environmental Degradation proposed by Erick Eckholm in the 1970s where overpopulation in Nepal hills was considered to be prime cause of Bangladesh effects through deforestation, denudation and soil erosion.

This was the dominant, neo-Malthusians discourse during the time of The Club of Rome, 1972, which projected overpopulation as the number one villain for all problems from environmental degradation to poverty, just as we have global warming and climate change as number one driver of global change in the popular imagination nowadays.

But even a neo-Malthusian such as Paul Ehrlich conceded that global environmental change was due to a number of factors in addition to population in his conceptual formula, IPAT, or environmental impact, I, as multiplicative product of population, P, affluence, A, and technology, T. Working on global land use and land cover change, Billie L Turner II and William B Meyer in 1995 proposed IPATIC, or the inclusion of institutions, I, and culture, C.

Different forms of institutions, defined as socially embedded system of rules such as law and marriage and organizations. For instance, Sanderson points out those institutional mechanisms of property rights and land reform are important to explain global land use change.

Culture deals with attitude and beliefs and a lot of land use decisions are based on such cultural norms and values according to Rockwell so they ought to be studied together with population and other explanatory variables of environmental change.

Although population has been considered an independent variable, authors such as Colin Sage advocate studying population and income together because they interact in complex and inseparable ways to affect land use.

The discourse on population and development is often alarmist and pessimist but the hazards school concentrating on why and how people adapt to risky situations offers hope. Of these, Regions at Risk, based on a global study of critical regions of the world by Kasperson et al of Clark University and published by the United Nations University Press, 1995, have looked into Nepal along with Amazon basin, the Ordos Plateau and Mexico City as a critical region.

They used common concepts and methods such as the trajectory of environmental change, well being, wealth along with concepts of environmental sensitivity and resilience. The authors classified risk into three categories: impoverished, endangered and critical.

“Critical” means that regional environmental change might continue through a trajectory of irreversible deterioration in this generation even when wealth and human well being were considered: such was the case for the Aral Sea.

Nepal was considered “Impoverished to Endangered” with some degree of certainty; in other words, there was some danger of irreversible environmental degradation in next two generations but there are also hopes of wealth generating human well being and resources for environmental stewardship. This was in 1995.

Today, 15 years later, we have some reasons for hope in the form of community forestry successfully greening the Nepal hills with the participation of nearly a third of the country’s population despite all the problems we have.

Nepal is progressing into the third stage of demographic transition from high birth and death rate to low death and birth rate and slowing population growth rate; the 2011 census is expected to confirm a declining population growth rate from 2.25 % a year to 2.17% or thereabouts.

Even development stands to take-off after real progress in the human development index and some lag time in the payoff in the investment in education and social transformation to a more equitable society where all the energies of the Nation will be released.

We are doing something right. The goal of this essay was to critically examine these outside the box discourses in population and development and consolidate such processes and forces for more efficient management of population and development.

Monday, July 18, 2011