diff --git a/alignment/alignment.cpp b/alignment/alignment.cpp
index c8e1bbd0a..153af9e30 100644
--- a/alignment/alignment.cpp
+++ b/alignment/alignment.cpp
@@ -21,7 +21,6 @@
 #include <Eigen/LU>
 #ifdef USE_BOOST
 #include <boost/math/distributions/binomial.hpp>
-#include <boost/container_hash/hash.hpp>
 #endif
 
 
diff --git a/tree/phylotreesse.cpp b/tree/phylotreesse.cpp
index 1d300594a..787c84c89 100644
--- a/tree/phylotreesse.cpp
+++ b/tree/phylotreesse.cpp
@@ -44,7 +44,7 @@ void PhyloTree::setNumThreads(int num_threads) {
     if (!isSuperTree() && aln && num_threads > 1 && num_threads > aln->getNPattern()/8) {
         outWarning(convertIntToString(num_threads) + " threads for alignment length " +
                    convertIntToString(aln->getNPattern()) + " will slow down analysis");
-        num_threads = max(aln->getNPattern()/8,1UL);
+        num_threads = max(aln->getNPattern()/8,(size_t)1);
     }
     this->num_threads = num_threads;
 }