diff --git a/Octokit.Reactive/Clients/IObservableTreesClient.cs b/Octokit.Reactive/Clients/IObservableTreesClient.cs
index ac10689a..5bcdf476 100644
--- a/Octokit.Reactive/Clients/IObservableTreesClient.cs
+++ b/Octokit.Reactive/Clients/IObservableTreesClient.cs
@@ -2,6 +2,12 @@ using System;
 
 namespace Octokit.Reactive
 {
+    /// <summary>
+    /// A client for GitHub's Git Trees API.
+    /// </summary>
+    /// <remarks>
+    /// See the <a href="http://developer.github.com/v3/git/trees/">Git Trees API documentation</a> for more information.
+    /// </remarks>
     public interface IObservableTreesClient
     {
         /// <summary>
@@ -13,10 +19,20 @@ namespace Octokit.Reactive
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1716:IdentifiersShouldNotMatchKeywords", MessageId = "Get")]
         IObservable<TreeResponse> Get(string owner, string name, string reference);
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#get-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1716:IdentifiersShouldNotMatchKeywords", MessageId = "Get")]
+        IObservable<TreeResponse> Get(int repositoryId, string reference);
+
         /// <summary>
         /// Gets a Tree Response for a given SHA.
         /// </summary>
@@ -26,9 +42,18 @@ namespace Octokit.Reactive
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         IObservable<TreeResponse> GetRecursive(string owner, string name, string reference);
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// https://developer.github.com/v3/git/trees/#get-a-tree-recursively
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        IObservable<TreeResponse> GetRecursive(int repositoryId, string reference);
+
         /// <summary>
         /// Creates a new Tree in the specified repo
         /// </summary>
@@ -38,7 +63,16 @@ namespace Octokit.Reactive
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="newTree">The value of the new tree</param>
-        /// <returns>The <see cref="TreeResponse"/> that was just created.</returns>
         IObservable<TreeResponse> Create(string owner, string name, NewTree newTree);
+
+        /// <summary>
+        /// Creates a new Tree in the specified repo
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#create-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="newTree">The value of the new tree</param>
+        IObservable<TreeResponse> Create(int repositoryId, NewTree newTree);
     }
 }
\ No newline at end of file
diff --git a/Octokit.Reactive/Clients/ObservableTreesClient.cs b/Octokit.Reactive/Clients/ObservableTreesClient.cs
index e018b10d..400c6d64 100644
--- a/Octokit.Reactive/Clients/ObservableTreesClient.cs
+++ b/Octokit.Reactive/Clients/ObservableTreesClient.cs
@@ -3,6 +3,12 @@ using System.Reactive.Threading.Tasks;
 
 namespace Octokit.Reactive
 {
+    /// <summary>
+    /// A client for GitHub's Git Trees API.
+    /// </summary>
+    /// <remarks>
+    /// See the <a href="http://developer.github.com/v3/git/trees/">Git Trees API documentation</a> for more information.
+    /// </remarks>
     public class ObservableTreesClient : IObservableTreesClient
     {
         readonly ITreesClient _client;
@@ -23,7 +29,6 @@ namespace Octokit.Reactive
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         public IObservable<TreeResponse> Get(string owner, string name, string reference)
         {
             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
@@ -33,6 +38,21 @@ namespace Octokit.Reactive
             return _client.Get(owner, name, reference).ToObservable();
         }
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#get-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        public IObservable<TreeResponse> Get(int repositoryId, string reference)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
+
+            return _client.Get(repositoryId, reference).ToObservable();
+        }
+
         /// <summary>
         /// Gets a Tree Response for a given SHA.
         /// </summary>
@@ -42,7 +62,6 @@ namespace Octokit.Reactive
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         public IObservable<TreeResponse> GetRecursive(string owner, string name, string reference)
         {
             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
@@ -52,6 +71,21 @@ namespace Octokit.Reactive
             return _client.GetRecursive(owner, name, reference).ToObservable();
         }
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// https://developer.github.com/v3/git/trees/#get-a-tree-recursively
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        public IObservable<TreeResponse> GetRecursive(int repositoryId, string reference)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
+
+            return _client.GetRecursive(repositoryId, reference).ToObservable();
+        }
+
         /// <summary>
         /// Creates a new Tree in the specified repo
         /// </summary>
@@ -61,7 +95,6 @@ namespace Octokit.Reactive
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="newTree">The value of the new tree</param>
-        /// <returns>The <see cref="TreeResponse"/> that was just created.</returns>
         public IObservable<TreeResponse> Create(string owner, string name, NewTree newTree)
         {
             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
@@ -70,5 +103,20 @@ namespace Octokit.Reactive
 
             return _client.Create(owner, name, newTree).ToObservable();
         }
+
+        /// <summary>
+        /// Creates a new Tree in the specified repo
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#create-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="newTree">The value of the new tree</param>
+        public IObservable<TreeResponse> Create(int repositoryId, NewTree newTree)
+        {
+            Ensure.ArgumentNotNull(newTree, "newTree");
+
+            return _client.Create(repositoryId, newTree).ToObservable();
+        }
     }
 }
diff --git a/Octokit.Tests.Integration/Clients/TreeClientTests.cs b/Octokit.Tests.Integration/Clients/TreeClientTests.cs
index 4522efc5..ea7d2b7e 100644
--- a/Octokit.Tests.Integration/Clients/TreeClientTests.cs
+++ b/Octokit.Tests.Integration/Clients/TreeClientTests.cs
@@ -2,8 +2,8 @@
 using System.Threading.Tasks;
 using Octokit;
 using Octokit.Tests.Integration;
-using Xunit;
 using Octokit.Tests.Integration.Helpers;
+using Xunit;
 
 public class TreeClientTests : IDisposable
 {
@@ -45,6 +45,31 @@ public class TreeClientTests : IDisposable
         Assert.NotNull(result);
     }
 
+    [IntegrationTest]
+    public async Task CanCreateATreeWithRepositoryId()
+    {
+        var blob = new NewBlob
+        {
+            Content = "Hello World!",
+            Encoding = EncodingType.Utf8
+        };
+
+        var createdBlob = await _github.Git.Blob.Create(_context.RepositoryOwner, _context.RepositoryName, blob);
+
+        var newTree = new NewTree();
+        newTree.Tree.Add(new NewTreeItem
+        {
+            Type = TreeType.Blob,
+            Path = "README.md",
+            Sha = createdBlob.Sha,
+            Mode = FileMode.File
+        });
+
+        var result = await _fixture.Create(_context.Repository.Id, newTree);
+
+        Assert.NotNull(result);
+    }
+
     [IntegrationTest]
     public async Task CanGetATree()
     {
@@ -54,6 +79,15 @@ public class TreeClientTests : IDisposable
         Assert.NotEmpty(result.Tree);
     }
 
+    [IntegrationTest]
+    public async Task CanGetATreeWithRepositoryId()
+    {
+        var result = await _fixture.Get(1, "master");
+
+        Assert.NotNull(result);
+        Assert.NotEmpty(result.Tree);
+    }
+
     [IntegrationTest]
     public async Task CanGetACreatedTree()
     {
@@ -82,6 +116,34 @@ public class TreeClientTests : IDisposable
         Assert.Equal(1, result.Tree.Count);
     }
 
+    [IntegrationTest]
+    public async Task CanGetACreatedTreeWithRepositoryId()
+    {
+        var blob = new NewBlob
+        {
+            Content = "Hello World!",
+            Encoding = EncodingType.Utf8
+        };
+
+        var blobResult = await _github.Git.Blob.Create(_context.RepositoryOwner, _context.RepositoryName, blob);
+
+        var newTree = new NewTree();
+        newTree.Tree.Add(new NewTreeItem
+        {
+            Type = TreeType.Blob,
+            Path = "README.md",
+            Sha = blobResult.Sha,
+            Mode = FileMode.File
+        });
+
+        var tree = await _fixture.Create(_context.Repository.Id, newTree);
+
+        var result = await _fixture.Get(_context.Repository.Id, tree.Sha);
+
+        Assert.NotNull(result);
+        Assert.Equal(1, result.Tree.Count);
+    }
+
     public void Dispose()
     {
         _context.Dispose();
diff --git a/Octokit.Tests/Clients/TreesClientTests.cs b/Octokit.Tests/Clients/TreesClientTests.cs
index 458f9a14..b876eeab 100644
--- a/Octokit.Tests/Clients/TreesClientTests.cs
+++ b/Octokit.Tests/Clients/TreesClientTests.cs
@@ -13,54 +13,86 @@ namespace Octokit.Tests
         public class TheGetMethod
         {
             [Fact]
-            public void RequestsCorrectUrl()
+            public async Task RequestsCorrectUrl()
             {
                 var connection = Substitute.For<IApiConnection>();
                 var client = new TreesClient(connection);
 
-                client.Get("fake", "repo", "123456ABCD");
+                await client.Get("fake", "repo", "123456ABCD");
 
                 connection.Received().Get<TreeResponse>(Arg.Is<Uri>(u => u.ToString() == "repos/fake/repo/git/trees/123456ABCD"));
             }
 
+            [Fact]
+            public async Task RequestsCorrectUrlWithRepositoryId()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new TreesClient(connection);
+
+                await client.Get(1, "123456ABCD");
+
+                connection.Received().Get<TreeResponse>(Arg.Is<Uri>(u => u.ToString() == "repositories/1/git/trees/123456ABCD"));
+            }
+
             [Fact]
             public async Task EnsuresNonNullArguments()
             {
                 var client = new TreesClient(Substitute.For<IApiConnection>());
 
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.Get(null, "name", "123456ABCD"));
-                await Assert.ThrowsAsync<ArgumentException>(() => client.Get("", "name", "123456ABCD"));
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.Get("owner", null, "123456ABCD"));
-                await Assert.ThrowsAsync<ArgumentException>(() => client.Get("owner", "", "123456ABCD"));
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.Get("owner", "name", null));
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Get(1, null));
+
+                await Assert.ThrowsAsync<ArgumentException>(() => client.Get("owner", "", "123456ABCD"));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.Get("", "name", "123456ABCD"));
                 await Assert.ThrowsAsync<ArgumentException>(() => client.Get("owner", "name", ""));
+
+                await Assert.ThrowsAsync<ArgumentException>(() => client.Get(1, ""));
             }
         }
 
         public class TheGetRecursiveMethod
         {
             [Fact]
-            public void RequestsCorrectUrl()
+            public async Task RequestsCorrectUrl()
             {
                 var connection = Substitute.For<IApiConnection>();
                 var client = new TreesClient(connection);
 
-                client.GetRecursive("fake", "repo", "123456ABCD");
+                await client.GetRecursive("fake", "repo", "123456ABCD");
 
                 connection.Received().Get<TreeResponse>(Arg.Is<Uri>(u => u.ToString() == "repos/fake/repo/git/trees/123456ABCD?recursive=1"));
             }
 
+            [Fact]
+            public async Task RequestsCorrectUrlWithRepositoryId()
+            {
+                var connection = Substitute.For<IApiConnection>();
+                var client = new TreesClient(connection);
+
+                await client.GetRecursive(1, "123456ABCD");
+
+                connection.Received().Get<TreeResponse>(Arg.Is<Uri>(u => u.ToString() == "repositories/1/git/trees/123456ABCD?recursive=1"));
+            }
+
             [Fact]
             public async Task EnsuresNonNullArguments()
             {
                 var client = new TreesClient(Substitute.For<IApiConnection>());
 
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetRecursive(null, "name", "123456ABCD"));
-                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("", "name", "123456ABCD"));
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetRecursive("owner", null, "123456ABCD"));
-                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("owner", "", "123456ABCD"));
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetRecursive("owner", "name", null));
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetRecursive(1, null));
+
+                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("", "name", "123456ABCD"));
+                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("owner", "", "123456ABCD"));
                 await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("owner", "name", ""));
+
+                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive(1, ""));
             }
         }
 
@@ -79,14 +111,30 @@ namespace Octokit.Tests
             }
 
             [Fact]
-            public async Task EnsuresArgumentsNotNull()
+            public void PostsToCorrectUrlWithRepositoryId()
+            {
+                var newTree = new NewTree();
+                var connection = Substitute.For<IApiConnection>();
+                var client = new TreesClient(connection);
+
+                client.Create(1, newTree);
+
+                connection.Received().Post<TreeResponse>(Arg.Is<Uri>(u => u.ToString() == "repositories/1/git/trees"), newTree);
+            }
+
+            [Fact]
+            public async Task EnsuresNonNullArguments()
             {
                 var connection = Substitute.For<IApiConnection>();
                 var client = new TreesClient(connection);
 
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.Create(null, "name", new NewTree()));
-                await Assert.ThrowsAsync<ArgumentException>(() => client.Create("", "name", new NewTree()));
                 await Assert.ThrowsAsync<ArgumentNullException>(() => client.Create("owner", null, new NewTree()));
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Create("owner", "name", null));
+
+                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Create(1, null));
+
+                await Assert.ThrowsAsync<ArgumentException>(() => client.Create("", "name", new NewTree()));
                 await Assert.ThrowsAsync<ArgumentException>(() => client.Create("owner", "", new NewTree()));
             }
 
@@ -102,6 +150,19 @@ namespace Octokit.Tests
                 await Assert.ThrowsAsync<ArgumentException>(
                     () => client.Create("fake", "repo", newTree));
             }
+
+            [Fact]
+            public async Task EnsureExceptionIsThrownWhenModeIsNotProvidedWithRepositoryId()
+            {
+                var newTree = new NewTree();
+                newTree.Tree.Add(new NewTreeItem { Path = "README.md", Type = TreeType.Blob, Sha = "2e1a73d60f004fd842d4bad28aa42392d4f35d28" });
+
+                var connection = Substitute.For<IApiConnection>();
+                var client = new TreesClient(connection);
+
+                await Assert.ThrowsAsync<ArgumentException>(
+                    () => client.Create(1, newTree));
+            }
         }
 
         public class TheCtor
diff --git a/Octokit.Tests/Reactive/ObservableTreesClientTests.cs b/Octokit.Tests/Reactive/ObservableTreesClientTests.cs
index d2e0920c..b94e211d 100644
--- a/Octokit.Tests/Reactive/ObservableTreesClientTests.cs
+++ b/Octokit.Tests/Reactive/ObservableTreesClientTests.cs
@@ -21,7 +21,7 @@ namespace Octokit.Tests
         public class TheGetMethod
         {
             [Fact]
-            public void GetsFromClientIssueIssue()
+            public void RequestsCorrectUrl()
             {
                 var gitHubClient = Substitute.For<IGitHubClient>();
                 var client = new ObservableTreesClient(gitHubClient);
@@ -31,24 +31,40 @@ namespace Octokit.Tests
                 gitHubClient.Git.Tree.Received().Get("fake", "repo", "123456ABCD");
             }
 
+            [Fact]
+            public void RequestsCorrectUrlWithRepositoryId()
+            {
+                var gitHubClient = Substitute.For<IGitHubClient>();
+                var client = new ObservableTreesClient(gitHubClient);
+
+                client.Get(1, "123456ABCD");
+
+                gitHubClient.Git.Tree.Received().Get(1, "123456ABCD");
+            }
+
             [Fact]
             public async Task EnsuresNonNullArguments()
             {
                 var client = new ObservableTreesClient(Substitute.For<IGitHubClient>());
 
-                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Get(null, "name", "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentException>(() => client.Get("", "name", "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Get("owner", null, "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentException>(() => client.Get("owner", "", "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentNullException>(() => client.Get("owner", "name", null).ToTask());
-                await Assert.ThrowsAsync<ArgumentException>(() => client.Get("owner", "name", "").ToTask());
+                Assert.Throws<ArgumentNullException>(() => client.Get(null, "name", "123456ABCD"));
+                Assert.Throws<ArgumentNullException>(() => client.Get("owner", null, "123456ABCD"));
+                Assert.Throws<ArgumentNullException>(() => client.Get("owner", "name", null));
+
+                Assert.Throws<ArgumentNullException>(() => client.Get(1, null));
+                
+                Assert.Throws<ArgumentException>(() => client.Get("", "name", "123456ABCD"));
+                Assert.Throws<ArgumentException>(() => client.Get("owner", "", "123456ABCD"));
+                Assert.Throws<ArgumentException>(() => client.Get("owner", "name", ""));
+
+                Assert.Throws<ArgumentException>(() => client.Get(1, ""));
             }
         }
 
         public class TheGetRecursiveMethod
         {
             [Fact]
-            public void GetsFromClientIssueIssue()
+            public void RequestsCorrectUrl()
             {
                 var gitHubClient = Substitute.For<IGitHubClient>();
                 var client = new ObservableTreesClient(gitHubClient);
@@ -58,24 +74,40 @@ namespace Octokit.Tests
                 gitHubClient.Git.Tree.Received().GetRecursive("fake", "repo", "123456ABCD");
             }
 
+            [Fact]
+            public void RequestsCorrectUrlWithRepositoryId()
+            {
+                var gitHubClient = Substitute.For<IGitHubClient>();
+                var client = new ObservableTreesClient(gitHubClient);
+
+                client.GetRecursive(1, "123456ABCD");
+
+                gitHubClient.Git.Tree.Received().GetRecursive(1, "123456ABCD");
+            }
+
             [Fact]
             public async Task EnsuresNonNullArguments()
             {
                 var client = new ObservableTreesClient(Substitute.For<IGitHubClient>());
 
-                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetRecursive(null, "name", "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("", "name", "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetRecursive("owner", null, "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("owner", "", "123456ABCD").ToTask());
-                await Assert.ThrowsAsync<ArgumentNullException>(() => client.GetRecursive("owner", "name", null).ToTask());
-                await Assert.ThrowsAsync<ArgumentException>(() => client.GetRecursive("owner", "name", "").ToTask());
+                Assert.Throws<ArgumentNullException>(() => client.GetRecursive(null, "name", "123456ABCD"));
+                Assert.Throws<ArgumentNullException>(() => client.GetRecursive("owner", null, "123456ABCD"));
+                Assert.Throws<ArgumentNullException>(() => client.GetRecursive("owner", "name", null));
+
+                Assert.Throws<ArgumentNullException>(() => client.GetRecursive(1, null));
+
+                Assert.Throws<ArgumentException>(() => client.GetRecursive("", "name", "123456ABCD"));
+                Assert.Throws<ArgumentException>(() => client.GetRecursive("owner", "", "123456ABCD"));
+                Assert.Throws<ArgumentException>(() => client.GetRecursive("owner", "name", ""));
+
+                Assert.Throws<ArgumentException>(() => client.GetRecursive(1, ""));
             }
         }
 
         public class TheCreateMethod
         {
             [Fact]
-            public void CreatesFromClientIssueIssue()
+            public void RequestsCorrectUrl()
             {
                 var newTree = new NewTree();
                 var gitHubClient = Substitute.For<IGitHubClient>();
@@ -87,16 +119,30 @@ namespace Octokit.Tests
             }
 
             [Fact]
-            public async Task EnsuresArgumentsNotNull()
+            public void RequestsCorrectUrlWithRepositoryId()
             {
+                var newTree = new NewTree();
                 var gitHubClient = Substitute.For<IGitHubClient>();
                 var client = new ObservableTreesClient(gitHubClient);
 
+                client.Create(1, newTree);
+
+                gitHubClient.Git.Tree.Received().Create(1, newTree);
+            }
+
+            [Fact]
+            public async Task EnsuresNonNullArguments()
+            {
+                var client = new ObservableTreesClient(Substitute.For<IGitHubClient>());
+
                 Assert.Throws<ArgumentNullException>(() => client.Create(null, "name", new NewTree()));
-                Assert.Throws<ArgumentException>(() => client.Create("", "name", new NewTree()));
                 Assert.Throws<ArgumentNullException>(() => client.Create("owner", null, new NewTree()));
-                Assert.Throws<ArgumentException>(() => client.Create("owner", "", new NewTree()));
                 Assert.Throws<ArgumentNullException>(() => client.Create("owner", "name", null));
+
+                Assert.Throws<ArgumentNullException>(() => client.Create(1, null));
+
+                Assert.Throws<ArgumentException>(() => client.Create("", "name", new NewTree()));
+                Assert.Throws<ArgumentException>(() => client.Create("owner", "", new NewTree()));
             }
         }
     }
diff --git a/Octokit/Clients/ITreesClient.cs b/Octokit/Clients/ITreesClient.cs
index 549621a4..b4835661 100644
--- a/Octokit/Clients/ITreesClient.cs
+++ b/Octokit/Clients/ITreesClient.cs
@@ -19,10 +19,20 @@ namespace Octokit
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1716:IdentifiersShouldNotMatchKeywords", MessageId = "Get")]
         Task<TreeResponse> Get(string owner, string name, string reference);
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#get-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1716:IdentifiersShouldNotMatchKeywords", MessageId = "Get")]
+        Task<TreeResponse> Get(int repositoryId, string reference);
+
         /// <summary>
         /// Gets a Tree Response for a given SHA.
         /// </summary>
@@ -32,9 +42,18 @@ namespace Octokit
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         Task<TreeResponse> GetRecursive(string owner, string name, string reference);
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// https://developer.github.com/v3/git/trees/#get-a-tree-recursively
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        Task<TreeResponse> GetRecursive(int repositoryId, string reference);
+
         /// <summary>
         /// Creates a new Tree in the specified repo
         /// </summary>
@@ -44,7 +63,16 @@ namespace Octokit
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="newTree">The value of the new tree</param>
-        /// <returns>The <see cref="TreeResponse"/> that was just created.</returns>
         Task<TreeResponse> Create(string owner, string name, NewTree newTree);
+
+        /// <summary>
+        /// Creates a new Tree in the specified repo
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#create-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="newTree">The value of the new tree</param>
+        Task<TreeResponse> Create(int repositoryId, NewTree newTree);
     }
 }
\ No newline at end of file
diff --git a/Octokit/Clients/TreesClient.cs b/Octokit/Clients/TreesClient.cs
index 5ac64675..4552b4f6 100644
--- a/Octokit/Clients/TreesClient.cs
+++ b/Octokit/Clients/TreesClient.cs
@@ -30,7 +30,6 @@ namespace Octokit
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         public Task<TreeResponse> Get(string owner, string name, string reference)
         {
             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
@@ -40,6 +39,21 @@ namespace Octokit
             return ApiConnection.Get<TreeResponse>(ApiUrls.Tree(owner, name, reference));
         }
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#get-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        public Task<TreeResponse> Get(int repositoryId, string reference)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
+
+            return ApiConnection.Get<TreeResponse>(ApiUrls.Tree(repositoryId, reference));
+        }
+
         /// <summary>
         /// Gets a Tree Response for a given SHA.
         /// </summary>
@@ -49,7 +63,6 @@ namespace Octokit
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="reference">The SHA that references the tree</param>
-        /// <returns>The <see cref="TreeResponse"/> for the specified Tree.</returns>
         public Task<TreeResponse> GetRecursive(string owner, string name, string reference)
         {
             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
@@ -59,6 +72,21 @@ namespace Octokit
             return ApiConnection.Get<TreeResponse>(ApiUrls.TreeRecursive(owner, name, reference));
         }
 
+        /// <summary>
+        /// Gets a Tree Response for a given SHA.
+        /// </summary>
+        /// <remarks>
+        /// https://developer.github.com/v3/git/trees/#get-a-tree-recursively
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="reference">The SHA that references the tree</param>
+        public Task<TreeResponse> GetRecursive(int repositoryId, string reference)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(reference, "reference");
+
+            return ApiConnection.Get<TreeResponse>(ApiUrls.TreeRecursive(repositoryId, reference));
+        }
+
         /// <summary>
         /// Creates a new Tree in the specified repo
         /// </summary>
@@ -68,7 +96,6 @@ namespace Octokit
         /// <param name="owner">The owner of the repository</param>
         /// <param name="name">The name of the repository</param>
         /// <param name="newTree">The value of the new tree</param>
-        /// <returns>The <see cref="TreeResponse"/> that was just created.</returns>
         public Task<TreeResponse> Create(string owner, string name, NewTree newTree)
         {
             Ensure.ArgumentNotNullOrEmptyString(owner, "owner");
@@ -82,5 +109,25 @@ namespace Octokit
 
             return ApiConnection.Post<TreeResponse>(ApiUrls.Tree(owner, name), newTree);
         }
+
+        /// <summary>
+        /// Creates a new Tree in the specified repo
+        /// </summary>
+        /// <remarks>
+        /// http://developer.github.com/v3/git/trees/#create-a-tree
+        /// </remarks>
+        /// <param name="repositoryId">The ID of the repository</param>
+        /// <param name="newTree">The value of the new tree</param>
+        public Task<TreeResponse> Create(int repositoryId, NewTree newTree)
+        {
+            Ensure.ArgumentNotNull(newTree, "newTree");
+
+            if (newTree.Tree.Any(t => string.IsNullOrWhiteSpace(t.Mode)))
+            {
+                throw new ArgumentException("You have specified items in the tree which do not have a Mode value set.");
+            }
+
+            return ApiConnection.Post<TreeResponse>(ApiUrls.Tree(repositoryId), newTree);
+        }
     }
 }