Both United Nations (UN) and Convention on Biological Diversity (CBD) recognized the importance of protected areas (PAs) as a key strategy for biodiversity conservation and sustainable development. This makes global protected areas an important contribution to achieving these commitments. However, PA coverage alone does not effectively measure the overall effectiveness of the protected areas performance or conservation success, thus the effectiveness of the curved or designated PAs needs to be monitored. This paper investigated the Effectiveness of National Parks and Game Reserves in Tree Species Conservation in Dry Region of North-East Nigeria by comparing Gashaka-Gumti national (GGNP) park and Yankari Game reserve (YGR). Wandering quarter method of vegetation analysis was employed as instrument for data generation where five sampling points (five vegetation zones in GGNP and four angles and centre in YGR) were established in each of the PA for data collection. Basal area, percentage frequency, relative density, relative dominance, importance value index were determined on each species encountered. Mean distance between tree stands, mean area as well as number of trees per hectare were also calculated. Results obtained indicated higher species diversity in GGNP over that of YGR (53 and 22 respectively). Basal area records indicated highest (34, 552.6cm) at GGNP on Uapaca togoensis against highest at YGR (25, 598.2 cm) on Khaya senegalensis. Same trend was observed on measures of Relative density, relative dominance and importance value indices (IVI). Going by the IVI, the vegetations of the PAs were described as Uapaca-Crossopteryx-Danielli complex and Kyaya-Combretum-Danielli type of vegetation in GGNP and YGR respectively. Values for mean distance (dm) between Trees, mean area (MA) occupied by Tree and Density of Trees per hectare indicated 3.4m, 11.6m & 862 in GGNP respectively against 6.2m, 38.4m, & 260 in YGR respectively