There are social and ecological problems associated with seasonal wildfire on forest and wildlife resources in Ogun State. These problems include loss of habitat, ecosystem destruction and loss of genetic biodiversity (Shotuyo, 2011). Seasonal wildfire results from indiscriminate setting of fire to vegetation during land preparation or in wildlife conservation areas. Brown and Davis (1973) reported that fire is a rapid, persistent chemical reaction that releases heat and light especially the exothermic combination of substances with oxygen. Such reaction is distinguished by magnitude, destructive power, utility or intensity. However, history reveals that fire is one of the earliest known tools used by man. In Nigeria or other parts of the world, man used fire to clear forest for agricultural purposes especially to increase food production. Specifically, in Nigeria, a farmer uses fire for his field clearing, a hunter in his game activities and a grazier in his pasture improvement efforts. These uses are exacerbated with the increasing population and intensified land use, resulting from increased demand for food supplies. Forest resources consist of an extremely wide diversity of flora and fauna; genetic resources which offer a broad array of goods and services with potential utilitarian application in agriculture, pharmaceutical industry, construction industry and rendered invaluable benefits and services especially in environmental protection. Falconer (1990) maintained that forests are traditionally valued as a source of timber, pulp and fuel. Other products classified as minor forest products are often products of industrial importance. The minor products include gums, resins and tannins. For rural inhabitants in forest regions, the forests are valued for a wide array of products.

Wildlife resources on the other hand also consist of wide diversity of fauna genetic resources which offer a broad array of goods especially protein where there is deficiency.

For avoidance of doubts, major forest environment include:
(a)   Tropical Rainforest: Tropical forest is rich in flora and fauna species with the plants and animals having no resistance to drought or cold. It occurs to a lesser extent in Africa.
(b)   Tropical Savanna: Dominated by grasses but dotted with trees or with patches or open forest. Some savannas are arid with scattered thorny trees; others have almost complete tree cover.
(c)   Deserts: Deserts occupy climate too dry for grassland. The vegetation consists of widely scattered thorny bushes and perhaps a few succulents such as Cacti of Euphobias and after rains small ephemeral annual plants.

The above are the ecosystems of forest resources and they are the terrestrial type.

Wildlife environment have been taken care of in forest resources because of the location of animal habitat and ecosystem within the forest. However, it suffices to mention major ecosystems within the wildlife resources. These are

(a)Arboreal ecosysytem
(b)Wetland ecosystem
(c)Unprotected Natural Areas

Man stand to gain a lot from conservation practices by preventing wildfire from seriously affecting forest and wildlife resources (Shotuyo, 2011). The primitive man, at least when his numbers were small, lived on the ecosystem without essentially destroying it. In order to produce more food and practise better agriculture, man started using fire as a tool for land clearing and preparation. This triggers factors into natural ecosystems and the beginning of purposefully modified systems (Bilings, 1978). These modified ecosystems are further threatened by over-exploitation resulting in unsustainable use for subsistence leading to impoverishment of forest and wildlife biodiversity or through development activities such as urbanization and modernization leading to sudden and often irreversible loss of biodiversity (Figure 1).
 

At present, about 70% of Nigeria’s tree populations are lost annually to forest fire (FAO, 1983,http://www.fao.org/fileadmin/user_upload/bodies/CFS_sessions/39th_Session/39emerg/MF027_CFS_39
_FINAL_REPORT_compiled_E.pdf). Forest crops valued at N19 million were destroyed by bush fire in Nigeria in 1983. Thus, forest resources are in decline because of over-exploitation. Several tree species over thousands of hectares including both matured, young and seedlings are destroyed at an alarming rate. As the forest is destroyed, the wildlife resources are not spared. In recent times, use of fire on wildlife resources resulted in a tremendous channelling of food energy into human populations especially the much required protein which is fairly expensive within the country. Pollock (1969) studied the records of European settlers and hunters in Africa in the 19th century and noted that during this period, wildlife was still abundant over most part of Africa. However, due to indiscriminate and unregulated hunting of wild fauna for food and trophies, wild animals have declined at an alarming rate in Africa during the 20th century especially in recent decades.

This paper discusses the impact of seasonal wildfire on forest and wildlife resources in artificial forest plantations and suggests ways of ameliorating these impacts on forest and wildlife biodiversity.

1 Sources and importance of wildfire
Wildfire has both natural and artificial origin. Wildfires occur in forest reserves and other bushes and plantation areas (FDF, 1986). The existence of favourable fire danger conditions like low humidity, high temperature, dry wind and sufficient dry matter together with human activities are found to be a major factor responsible for fire occurrence in Nigeria.

Brown and Davis (1973) enumerated eight causes of forest fire in the United States. These are: natural – lightening and friction due to objects robbing together and artificial – campfire, debris burning, incendiary, lumbering, railroad, smokers and miscellaneous. It is therefore evidence that major causes of wildfire are of artificial sources resulting from human activities towards economic emancipation.

Clarke and Show (1953) described lightning as a cause of fire with the natural phenomenon reaching its peak in the rocky mountains of Canada and the United States. However, in many other parts of the world, it is of no great importance. Luke and McArthur (1978) maintained that fire under rail roads included not only the fires started by locomotive sparks and other causes incidental to operating trains but also fires caused in the course of construction or maintenance of the right of way. Brown and Davis (1973), described debris burning as any fire spreading from a fire set to burn rubbish or garbage or for the purpose of land clearing, range, stubble or meadow burning and accounts for 28% of forest fire in United States. Smokers and campfires have been described by different authors as almost entirely due to carelessness in one form or another since there is no positive motive to set such fire. The burning of dead leaves and debris contributed immensely to wildfire.

The significant of wildfire on forest and wildlife biodiversity is very destructive and is worthy of note. FAO (1953) and Tilman et al (1966) described fire as the greatest enemy of forest resources. Wildfire is unplanned or uncontrolled burning and is therefore very destructive. Wildfire results in loss of vegetation, destruction of ecosystem which leads to loss of habitat and a disturbance of biology of a variety of wild animals. Billings (1978), reported that the destruction of ecosystems by man came along with civilization whether or not man needed the land for agriculture or just for a quick harvest of certain natural resources. Examples are numerous: the cutting, burning and abandonment of forestland, overhunting and elimination of big grazing animals such as okapi and elephants in Africa, bison in North America etc. leads to loss of biodiversity.

Migrated species of wild animals into ecosystems or inter-ecosystem movement of animals producing new species habitable to the new environment and increasing genetic reserve are destroyed during wildfire. It is therefore sad watching plantations and reserves established and maintained at great cost disappearing in smoke. FDF (1986) reported that about 30% of forest lands in some states of Nigeria is burnt down every year with the loss running into hundreds of thousands of naira including biodiversity. The summary of the consequences of fire on vegetation, animals and soil are enormous. It causes change on vegetation covers, defoliation, reduction in both tree height and diameter growth which may lead to stunted growth and poor bole form. Fire weakens trees, makes them lose growth and may later be attacked by insects. Fire can affect the number and rate of activities of soil organisms, remove or change the rate of soil organic matter formation and accumulation. Surface compactness and essential nutrients availability are equally influenced by fire. Fire eventually reduces animal population and to an extent irreparable loss of biodiversity.

2 Periods of wildfire
Wildfire occurs more frequently during the dry season between the months of December and March, when the air temperature is high and relative humidity and fuel loads moisture content are low (Adegbola, 1985). Vegetation is set ablaze annually between November and January (Early burning) or from February to the beginning of rains (late burning) .Early burning is done to provide early bush of palpable tender grass for livestock needing in areas of wildlife conservation. Despite the value of early burning, such fires are uncontrolled and therefore penetrate ecosystems leading to loss of biodiversity. Late burning is done to hunt for game animals by hunters and farmers and are set indiscriminately, burning all fuels along its course and coming to rest after much destruction when there is no more fuel within an ecosystem (Plate 1).
 

3 Observed effects of fire on plants and animals
The ability of a tree cambium to withstand fire intensities of different durations is dependent on bark thickness and bark thermal properties (Adegbola, 1985; Coppedge et al., 1998). This is due to the fact that fire decreases the density of woody stems and that late burning has a marked effect than early burning. Experiments have been carried out by Forestry Institute of Nigeria on the effect of burning on trees since 1929. The experiments were carried out on 0.17 hectare each for each treatment. The plots were separated by fire traces of 3.3 m wide (Plate 2).

The treatments given to the plots are stated below:

Plot A: annual burning late in the dry season (mid-march)
Plot B: annual burning early in the dry season (December)
Plot C: no treatment (protected from fire).

The summary of the fire effects is presented in tabular form below.
 

Table 1 data showed that there was general decrease in number of trees in all the three plots. Late burnt plot had the highest mortality while protected plot recorded the least mortality rate between 1991 and 1995. Decrease in trees in plots A and B is attributed to the effect of fire while in plot C decrease is attributed to natural mortality as dictated by prevailing climatic factors.
 

Equally, the effects of fire on wildlife resources was observed through farming activities which encouraged the destruction of ecosystem or the emergence of modified ecosystem to boast food production. In farming, forest is cut down and fire is employed as a tool for clearing. Accordingly, Adewale (1997, unpublished data) reported the effect of wildfire on wildlife biodiversity in a study carried out in Abeokuta game animal populations in farmlands with secondary forest regrowth. The method used was mark and recapture method to prevent over-estimation of species and population. The treatment used on the farm is stated below:

All sample plots: traps set in evening and inspected every morning. The traps were baited with cassava, maize and oil palm fruits. Every morning, captured rodents were marked; number captured recorded and released back into the surrounding. Rodents were marked by clipping their ears, toes or tails. The observation lasted for two months.
 

Table 2 data showed that large wild animals have migrated out of the modified ecosystem or trapped and killed by fire during land preparation. However, days without data had no animal information for the days.

Wildfire runs through ecosystem destroying habitat, trapping and killing animals, increasing animal susceptibility to diseases and encouraging new pathogens that further cause death of animals (Plate 3). In addition, some species of animals are lost completely in such inferno while others may not be able to exist within the ecosystem. Thus, there is loss of biodiversity.
 

4 Strategies for conservation
The need for forest and wildlife conservation for genetic preservation, quantity and acceptable quality to meet the domestic, industrial, resources population manipulation and recreational requirement require adequate concentration. In order to ensure sustainable utilization of forest and wildlife resources, there is need to ensure control of wildfire in all ecosystems through enforcement of adequate legislation and establishment of monitoring stations in areas prone to wildfire.

It is important to establish well-equipped and adequately staffed fire stations in strategic locations that will ensure prompt attention to fire outbreaks. To ensure that even if there arises any situation of unplanned fire outbreaks, they can be quickly and adequately controlled by these stations. The role of a well-coordinated anti-indiscriminate fire campaign cannot be over emphasised. This will go a long way in creating awareness about the debilitating effect of uncontrolled fire in any ecosystems.

References
Adegbola P.O., 1985, Detection and suppression of forest fires in Nigeria situation, Proceedings of seminar on Forest Fire Protection, Oluwa, Ondo State, pp.13-17

Billings W.D., 1978, Plants and the Ecosystem, Third Edition, Wadsworth Publishing Company, Inc, USA, pp.148-153

Brown A.A., and Davis K.P., 1973, Forest fire: Control and use, Second Edition, McGraw-Hill, USA, pp.544

Clarke B., and Show S.B., 1953, Elements of forest fire control, FAO, Rome, Italy, pp.2-17

Coppedge B.R., Engle D.M., Toepfer C.S., and Shaw J.H., 1998, Effects of seasonal fire, bison grazing and climatic variation on tall grass prairie vegetation, Plant Ecology, 139(2): 235-246
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Falconer J. prepared, Koppell C.R.S. ed., 1990, The major significance of minor forestry products: The local use and value of forests in the west african humid forest zone. Rome, FAO

FDF, 1986, Federal Department of Forestry, Nigeria. Pre-feasibility Study for National Forest Fire Service. Prepared by the Consultancy Services Unit

Luke R.H., and McArthur A.G., 1978, Bushfires in Australia, Canbera, Australian Government Publishing Service, pp. 359

Pollock A.L., 1969, Population Trends in African Wildlife Management. East African Wildlife Journal, Mireku, Monshi, Tanzania

Shotuyo, A.L.A., 2011, Vertebrate biodiversity in Alabata Nature Reserve, South West Nigeria: Nascent Nature Reserve, vertebraate survival strategies and the effects of wild fire, LAP LAMBERT Academic Publishing Heinrich- Böcking-Str, Aarbrücken, Germany pp.6-8   

Tilman D., Wedlin D., and Johannes K., 1966, Productivity and Sustainability influenced by biodiversity in grassland ecosystem, Nature, 379: 718-720
http://dx.doi.org/10.1038/379718a0