diff --git a/src/flexcode/regression_models.py b/src/flexcode/regression_models.py
index cb42678..d26308f 100644
--- a/src/flexcode/regression_models.py
+++ b/src/flexcode/regression_models.py
@@ -52,7 +52,8 @@ def __init__(self, max_basis, params):
             raise Exception("RandomForest requires sklearn to be installed")
 
         super(RandomForest, self).__init__(max_basis)
-        self.models = [sklearn.ensemble.RandomForestRegressor()
+        self.n_estimators = params.get("n_estimators", 10)
+        self.models = [sklearn.ensemble.RandomForestRegressor(self.n_estimators)
                        for ii in range(self.max_basis)]
 
     def fit(self, x_train, z_basis):
@@ -68,12 +69,15 @@ def predict(self, x_test):
 
 class XGBoost(FlexCodeRegression):
     def __init__(self, max_basis, params):
+        if not XGBOOST_AVAILABLE:
+            raise Exception("XGBoost requires xgboost to be installed")
         super(XGBoost, self).__init__(max_basis)
 
         self.params = {'max_depth' : params.get("max_depth", 6),
                        'eta' : params.get("eta", 0.3),
                        'silent' : params.get("silent", 1),
-                       'objective' : 'reg:linear'}
+                       'objective' : params.get("objective", 'reg:linear')
+                      }
         self.num_round = params.get("num_round", 500)
 
     def fit(self, x_train, z_basis):