The Sky Canopy Gap Irradiance (SCANGIR) Model: a technique for the estimation of ‘effective gap’ solar radiation regimes in closed-canopy forests

There is now widespread consensus among researchers that treefall gaps play a key role in the structure and function of closed-canopy forests, such as rain forests, with virtually all canopy tree species requiring growth in a gap to reach maturity. Until recently many believed that latitude and the size of treefall gaps were the main factors determining the availability of solar radiation in gaps and associated microclimates and vegetation dynamics. However, if solar radiation availability is the main limiting resource in such forests, then studies of gap dynamics need to take into account the other factors affecting the penetration and distribution of direct and diffuse irradiance within gaps. As a consequence, this is the first attempt to develop a universal model for the estimation of ‘effective gap’ solar radiation regimes that, along with latitude and gap size, incorporates factors such as slope angle, slope aspect, height of surrounding vegetation, sky conditions and daily and seasonal variation in the position of the sun. Results of three computer simulations are presented to demonstrate how latitude, topography and sky conditions affect solar radiation availability beneath circular canopy gaps of various configurations. Finally, the implications of these simulations for forest regeneration, reforestation and forest management are discussed.     

Book reviews

Adam Watson, Diplomacy: the dialogue between states. Eyre Methuen, London, 1982, pp.239. $28.95.

Desmond Ball and J.O. Langtry (eds). Civil Defence and Australia's Security in the Nuclear Age. Strategic and Defence Studies Centre, Australian National University, Canberra, and George Allen and Unwin Australia, Sydney. 1983, pp. 359. $12.95.

Bruce Grant, Gods and Politicians. Allen Lane, Ringwood, Victoria, 1982, pp.wi + 190. $16.95.

B.A. Santamaria, Santamaria, Against the Tide. Oxford University Press, Melbourne, 1981, pp. 382. $22.50

M.M. Kritz. C.B. Keely and S.M. Tomasi (eds.), Global Trends in Migration: Theory and Research on International Population Movements. The Centre for Migration Studies, New York, 1981, pp.xi + 433. $US14.95 (cloth), $US9.95 (paper).

Robert Cassen, Richard Jolly, John Sewell and Robert Wood (eds). Rich Country Interests and Third World Development. Croom Helm, London and Canberra, 1982, pp. 369. $27.75.

David Childs, The GDR: Moscow's German Ally. George Allen and Unwin, London, 1983, pp. xiii + 346. $49.95 (cloth), $19.95 (paper).

Alexander Shtromas, Political Change and Social Development; The Case of the Soviet Union. Verlag Peter Lang, Bern, 1981, pp 173. S Fr 40.

Joel K. Goldstein, The Modern American Vice Presidency. The Transformation of a Political Institution. Princeton University Press, Princeton, N.J., 1982, pp. xxii + 409. $US36.50 (cloth) $US 10.50 (paper).

Colin Mackerras, Modern China ‐ A Chronology from 1842 to the Present. Thames and Hudson, London, 1982, pp. 703. $60.00

John H. Fincher, Chinese Democracy: The Self Government Movement in Local. Provincial and National Politics, 1905–1914. Australian National University Press, Canberra, 1981, pp. 27s6. $23.95.

A.J. Youngson, Hong Kong: Economic Growth and Policy. Oxford University Press, Hong Kong, 1982, pp. 163. $10.95.

Peter Wesley‐Smith, Unequal Treaty 1898–1997: China. Great Britain and Hong Kong's New Territories. Oxford University Press, Hong Kong. 1980, pp. XV + 270. $39.00.

Michael Leifer, Indonesia's Foreign Policy. George Allen & Unwin, London, 1983, pp. xvii + 198. $39.95.

Grant Evans, The Yellow Rainmakers. New Left Books/Verso, London, 1983, pp. 202. $33.50 (cloth) $10.50 (paper).

Stewart Firth, New Guinea Under the Germans. Melbourne University Press, Melbourne, 1982, pp. xiii + 216. $25.00.

R.J. May (ed.), Micronationalist Movements in Papua New Guinea. Political and Social Change Monograph No. 1, Department of Political and Social Change, Research School of Pacific Studies, Australian National University, Canberra, 1982, pp. xi. + 486 $9.50.

Politics in Melanesia. Institute of Pacific Studies, University of the South Pacific, Suva, 1982, pp. xxi + 170. $4.00

Foreign Forces in Pacific Politics. Institute of Pacific Studies, University of the South Pacific, Suva, 1983, pp. xv + 325, $6.00.

Mike Moore, A Pacific Parliament. Asia Pacific Books, Wellington and the Institute of Pacific Studies, University of the South Pacific, Suva, 1982, pp. 86. No price given.

Australia and the South Pacific. Conference Papers and Reports. Centre for Continuing Education, Australian National University, Canberra, 1983, pp. 157. $8.00.

Alan R. Taylor, The Arab Balance of Power, Syracuse University Press, Syracuse, 1982, pp. xii + 165. $US22.00 (cloth) $US11.95 (paper).

Tareq Y. Ismael, Iraq and Iran: Roots of Conflict. Syracuse University Pess. Syracuse. 1982, pp xii + 226. $US24.00 (cloth) $US12.95 (paper).

Peter Gubser, Jordan: Crossroads of Middle Eastern Events. Croom Helm, London and Westview Press, Boulder, Colorado, 1983, pp. xi+ 139. £13.50.

Ibrahim Ibrahim (ed.), Arab Resources: The Transformation of a Society. Croom Helm, London, 1983, pp. 304. $24.25.

David Goldsworthy, The International Politics of the Namibian Dispute, Discussion Paper No. 3, 1982, pp. 41

Jock McCulloch, South Africa's Invasion of Angola: Many Reasons Why. Current Issues Brief No. 7, 1981, pp. 10 both published by the Legislative Research Service, Department of the Parliamentary Library, Canberra.     

The regional consequences of a dualistic industrial structure: the case of Australia

This article is a preliminary attempt to consider the spatial consequences of business organisation segmentation in the Australian economy. The first section outlines a framework that can be employed in an analysis of business organisation segmentation. The second section applies this framework in the context of the Australian economy. This section is in three parts. First, it is shown that conventional sectoral data can be used to approximate business organisation segmentation. Second, the labour market consequences of this empirical exercise are documented. Finally, the spatial consequences of the exercise are shown by way of a series of maps.     

The changing pattern of urban fertility in eastern Australia 1966–1976

The article seeks to enhance understanding of post-transitional demographic change by examining the working out at the local level of the macro-scale societal processes underpinning the recent cyclic oscillation in Australian reproductive behaviour. Variations in urban marital and overall fertility between 1966 and 1971 and between 1971 and 1976 are described and analysed. In general, inter-urban variability in both measures diminished greatly, as did the explanatory power of ecological differentials, suggesting widespread acceptance of the small family norm throughout the study-area. While the process of convergence was continuous for marital fertility, structural changes contributed to later divergence of overall fertility levels, in accordance with Alonso's cyclical model of change. The current low level of residual inter-urban variability suggests that little more may be gained from analyses of this type.