PRICE VARIATION AND MOVEMENT OF Halea ciliata SPECIES OF LUMBER IN DELTA STATE, NIGERIA

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INTRODUCTION
In the author's opinion, majority of forest product markets in Nigeria are poorly integrated. Unity and efficiency in price movement is important for development of products markets, especially in ensuring uniformity in economic wellbeing and production cost across spatial markets (Michal and Patrick, 2020). When there is uniformity in price information, strong market integration exist, showing the existence of soaring level of competition and connection between or among such markets (Birge et al., 2020). Market strongholds and transportation challenges are some of the major causes of price inequality between markets with consequence of poor market integration (Martinez-de and Vendrell, 2017). Studying efficient marketing of products harvested from the forest in Nigeria is important for Forestry sector development. It has two major importance; stakeholder's satisfaction and environmental sustainability, especially as forests (it trees, land and other resources) are regarded as the earth lungs. Therefore, the market for products harvested from the forest is dynamic. Lumber, obtained from tree and processed in sawmills is a key marketable wood product in Nigeria. Its uses are vast and the harvesting of trees for lumber is a main cause of forest degradation (Igben and Ohiembor, 2015). This is further heightened as majority of local and urban dwellers livelihood depend on trade in forest products (Pandey et al., 2016).
Variation exists in mechanical characteristics of lumber gotten from various species, hence their grading and demand. The grading of lumber into categories after processing helps to influence the value and likely use possible for each board of lumber (Michael et al., 2017). The prices of lumber also vary with species even with their grading. This price disparity boosts excessive lumber production and sales in areas with lower price (Yogisha, 2006). The impact is intense deforestation in those areas. Despite the uniqueness of forest ecosystem and the prolonged effect of deforestation, movement of lumber prices between markets in the state for various species is scarce. Ohwo and Adeyemi (2015) examined market integration of Poga oleosa species of lumber. Investigation of other species is important to have an understanding of lumber market performance in Delta State.

MATERIALS AND METHODS The Study Area
The study was conducted in Delta, a State rich with diverse timber species from its rainforest, Nigeria. It is situated between longitude 5º00ˡ and 6º45ˡ East and latitude 5º00ˡ and 6º30ˡ North ( Figure 1). As a result, there exist various sawmill and lumber markets.

Sampling Procedure
Three (3) informants each were selected purposively from local and urban lumber markets in the 25 Local Government Area of the State. The criterion for selection was based on years in business. Informants that have spent over 10 years in lumber sells were interviewed for the study. An 150 lumber sellers were sampled.

Method of Data Collection
Price data were obtained monthly for three (3) volumes (0.013m 3 , 0.019m 3 and 0.025m 3 ) of Halea ciliata species of lumber (2010-2019) from sales records of lumber sellers in local and urban lumber markets (LUM).

Method of Data Analysis
Econometric analysis of Unit Root Test, Augmented Dickey Fuller, Ravallion IMC model, Engle and Granger (1987) test of co-integration and error correction model (ECM) were data analytical tools employed to test for the presence of unit root and price information flow amongst the local and urban markets.

RESULTS AND DISCUSSION
The average monthly price movement of Halea ciliata and the various volumes for urban and local lumber markets (Figures 2 to 4) were characterized by fluctuation. There was an increment in prices of lumber in LUM from 2010 to 2019. The price fluctuated from N240 in January 2010 to N470 in January 2019 for the 0.013m 3 volume in the urban market (UM), while in local market (LM), price rose from N270 in January 2010 to N480 in 2019. For 0.019 m 3 lumber volume, UM prices increased from N370 in January 2010 to N590 in January 2019 while the LM trend from N380 in January 2010 to N620 in January 2019. For 0.025m 3 volume, price rose from N480 in January 2010 to N780 in January 2019 and N490 in January 2010 to N740 in 2019 for urban and local lumber markets, respectively.

Test of Stationarity for Prices of Halea ciliata Species of Lumber
The findings revealed the acceptance of non-stationarity in the various volumes at level forms (Table 1). The hypothesis of non-stationarity was rejected at first differential. This conforms to reports of Ajibade et al. (2018), Ajibade et al. (2019) and Pei-Tha et al. (2020), that prices of commodity may contain unit root at first difference. Therefore, the variables were subjected to co-integration test and were integrated without unit root in the same order I (1). Source: Data analysis (2020)

The Ravallion IMC Analysis
High short-run price movement exists for all volumes of Halea ciliata lumber considered ( Table 2). The 0.025 m 3 and 0.019 m 3 volumes had the peak and least IMC value of -0.23 and -7.66, respectively. The extent of market integration is quantified by the closeness of IMC values to zero. There exist great level of market integration and efficiency when IMC value is closer to zero. The result shows that price movement of lumber occurs monthly across markets. Using the IMC as substitute for efficiency, the volumes of H. ciliata in paired markets indicate efficiencies showing low discrepancy in spatial prices. This observation negates that of Africa Growth Initiative (2016) who stated that forest pricing system and markets in third world countries are inefficient.

Engle-Granger Co-integration Analysis
The result using the Engle Granger critical values showed that market for all volumes of H. ciliata co-integrated (Table 3) (Trace statistics (TS) < critical values (CV) at P< 0.05). The H0 was rejected. H. ciliata species of 0.019 m 3 had the topmost TS of -3.8793 and 0.025 m 3 had the least TS of -10.8590. The implication is that prices movement is evident for all volumes of H. ciliata species in the long run. Hence, prices in LM is useful in the prediction of that of UM and vice versa as observed by Iheke and Obasi (2017) and Ajibade et al. (2019).

Error Correction Mechanism Analysis (ECM)
The intensity of price variation transfer from local to urban lumber markets is shown in the ECM result in Tables 4. The ECM shows the velocity of price movement towards balance in the short possible time. Its coefficient reflects the time involved in price movement to evenness in one month. The nearness to one the ECM coefficient, the faster lumber prices attains equilibrium. The ECM values are negative and different from zero statistically. The greater the ECM values, the lesser time prices reaches equilibrium, the enhanced the integration of market and vice versa (Goletti et al., 1995). The ECM coefficient results for all volumes of H. ciliata species were significant (P<0.05). The least and highest value of -0.4857 and -0.9820 was attained for 0.025m 3 and 0.013 m 3 , respectively, in Local -Urban markets. The peak value implies there is 98% immediate alteration of lumber prices in local and urban lumber market in one month. The implication is that elevated level of price movement and efficiency exist for 0.025m 3 of lumber.

CONCLUSION AND RECOMMENDATION
The study examined price movement as proxy for efficiency of lumber market of H. ciliata in LUM of Delta State. The prices of three volumes of lumber (0.013m 3 , 0.019m 3 and 0.025m 3 ) from 2010 to 2019 were examined. The price data contained unit root in level form but, absent at first difference. The markets for lumber were efficient with about 98% rapid movement of price for 0.025m 3 monthly. The encouragement of forest restoration and tree planting for continuous supply of lumber to the market is recommended from the study.