destructor of binary tree

I am writing some codes to implement a binary tree, which basically
looks like:

class BTree {
    BTree(BTree &); // prevent copy-construction
    BTree * pRight;
    BTree * pLeft;
    double value;

    public:
    BTree(double value): value(value), pRight(0), pLeft(0) {};

    void setRightBranch(BTree * pbt) {
        pRight = pbt;
    }

    void setLeftBranch(BTree * pbt) {
        pLeft = pbt;
    }
    // and the rest code
}

I might create instances of BTree both statically or dynamically, i.e.
both of the following two ways will be used:

BTree bTree(1.0);
or
BTree * pBTree = new BTree(1.0);

To manage the memory allocation in the dynamic creation of the
instances, I need a recursive destructor, which I would like to
implement as follows:

~BTree() {
    if(pRight != 0) // not the end
         delete pRight;
    if(pLeft != 0) // not the end
         delete pLeft;
}

This destrucotr works fine for a tree whose nodes are all created by
the new-operator, e.g.

BTree * pbt1= new BTree(1.0);
BTree * pbt2= new BTree(2.0);
BTree * pbt3= new BTree(3.0);
pbt3->setLeftBranch(pbt1);
pbt3->setRightBranch(pbt2);

delete pbt3;

However, if I have statically created tree in my program, e.g.

BTree bt1(1.0);
BTree bt2(2.0);
BTree bt3(3.0);
bt3.setLeftBranch(bt1);
bt3.setRightBranch(bt2);

At the end of the scope, the destructor of bt3 will be called and the
line "delete pRight;" and "delete pLeft;" will be carried out to the
instances, bt1and bt2, which are not created by new-operator.

I wonder how should I implement this destructor so it works for both
statically created instances and dynamically created instances.
Thanks!