diff --git a/apps/traincascade/boost.cpp b/apps/traincascade/boost.cpp
index 0ba11a936..2d29f338b 100644
--- a/apps/traincascade/boost.cpp
+++ b/apps/traincascade/boost.cpp
@@ -489,8 +489,8 @@ void CvCascadeBoostTrainData::setData( const CvFeatureEvaluator* _featureEvaluat
     int* idst = 0;
     unsigned short* udst = 0;
 
-    uint64 effective_buf_size = -1;
-    int effective_buf_height = -1, effective_buf_width = -1;
+    uint64 effective_buf_size = 0;
+    int effective_buf_height = 0, effective_buf_width = 0;
 
 
     clear();
diff --git a/modules/ml/src/tree.cpp b/modules/ml/src/tree.cpp
index 583cd33ba..1ba94fcaf 100644
--- a/modules/ml/src/tree.cpp
+++ b/modules/ml/src/tree.cpp
@@ -159,8 +159,8 @@ void CvDTreeTrainData::set_data( const CvMat* _train_data, int _tflag,
     char err[100];
     const int *sidx = 0, *vidx = 0;
 
-    uint64 effective_buf_size = -1;
-    int effective_buf_height = -1, effective_buf_width = -1;
+    uint64 effective_buf_size = 0;
+    int effective_buf_height = 0, effective_buf_width = 0;
 
     if( _update_data && data_root )
     {