NOVELTY - Treating (M1) a cellulosic material, involves: extracting the cellulosic material with an extractant to selectively extract hemicellulose, where the extractant comprises an amine oxide and a non-solvent; and separating the extracted hemicellulose from the cellulosic material to form a cellulosic product comprising less hemicellulose than the cellulosic material.    USE - For treating a cellulosic material for forming cellulosic product; for producing high purity alpha -cellulose grade pulp; and for reducing hemicellulose in a cellulosic material to form a hemicellulose reduced product (claimed).    ADVANTAGE - The cellulosic product formed by this method retains a cellulosic fiber morphology. The purified wood pulp product maintains a cellulosic morphology. The method treats cellulosic material to selectively extract hemicellulose in it and separating the extracted hemicellulose to form a cellulosic product comprising less hemicellulose than the cellulosic material. The methods are effective methods for removing hemicellulose from cellulosic materials to recover high purity alpha -cellulose that can be converted to other cellulose derivatives such as cellulose ether, cellulose esters, cellulose nitrate, cellulose acetate, other derivatives of cellulose, and regenerated cellulose fiber such as viscose, lyocell, and rayon. The method forms purified wood pulp product that retains a cellulosic fiber morphology and other suitable characteristic such as intrinsic viscosity and brightness.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a cellulosic product made by the method (M1);    (2) producing (M2) high purity alpha -cellulose grade pulp, involving: extracting hemicellulose from a wood pulp by treating the wood pulp with an extractant comprising an amine oxide and a non-solvent to form an intermediate wood pulp that retains a cellulosic fiber morphology; treating the intermediate wood pulp with an enzyme to hydrolyze the hemicellulose contained in it to form a reduced hemicellulose wood pulp; and washing the reduced hemicellulose wood pulp with a wash solution to form the high purity alpha -cellulose grade pulp;    (3) a high purity alpha -cellulose grade pulp product purified by removing hemicellulose from cellulosic material using a mixture (T1) of amine oxide and water, where the high purity alpha -cellulose grade pulp product comprises less than 5% hemicellulose;    (4) a solvent system (S1) for reducing hemicellulose in a cellulosic material to form a hemicellulose reduced product, comprising 50-80 wt.% amine oxide and 20-50 wt.% water; and    (5) a solvent system for selectively reducing hemicellulose in a cellulosic material to form a hemicellulose reduced cellulosic product, comprising at most 40 wt.% amine oxide, at most 12.5 wt.% water, and at least 50 wt.% dimethyl sulfoxide.