Table S1. List of mycorrhyzal OTUs detected on roots of silver birch and hybrid aspen roots																																																
																																																
																																																
Host	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Hybrid aspen	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Hybrid aspen	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch	Silver birch
Clone	44	44	44	43	43	43	43	43	44	44	44	43	43	43	44	44	44	43	43	43	44	44	44	54-146-143	54-146-143	54-146-143	54-146-143	54-146-143	54-146-143	55-875	55-875	55-875	54-146-143	54-146-143	54-146-143	54-146-143	54-146-143	54-146-143	55-875	43	55-875	55-875	55-875	55-875	55-875	55-875	55-875	55-875
Field pefrormance	high	high	high	moderate	moderate	moderate	moderate	moderate	high	high	high	moderate	moderate	moderate	high	high	high	moderate	moderate	moderate	high	high	high	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate	moderate
sample/OTUs	A39_13	A39_7	A39_9	A41_13	A41_9	A47_13	A47_7	A47_9	A52_12	A52_14	A52_8	A56_14	A56_18	A56_8	A58_14	A58_18	A58_8	A60_12	A60_14	A60_8	A61_13	A61_19	A61_23	J100_13	J100_18	J100_9	J108_13	J108_14	J108_9	J126_12	J126_19	J126_9	J140_10	J140_13	J140_9	J46_17	J46_8	J46_9	J47_18	A47_17	J47_8	J47_9	J61_13	J61_8	J61_9	J63_12	J63_13	J63_18
Inocybe sp	0	12	3	7	17	258	31	15	9	0	625	30	22	17	4	10	2	27	11	125	9	113	51	30	26	0	76	115	25	41	40	57	30	25	13	210	85	41	68	15	39	39	24	60	18	5	22	12
Tomentella stipitobasidia	0	437	0	0	2	17000	12	139	62	39	601	0	0	5	77	556	2	2355	3552	3867	46	1582	1369	5980	2739	36	124	2	439	4188	87	644	217	74	6	5230	16653	21903	11068	38	1121	28824	45	8266	207	19637	4334	759
Hebeloma matritense	12	0	2807	349	2007	5638	468	6697	11091	11268	743	44	0	2383	0	26	0	0	21	3252	0	411	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	152	0	0
Hymenogaster griseus	6	0	0	0	5499	0	209	2597	0	0	0	311	2	6	401	932	2	19	0	272	4	0	421	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	19	0	0	0	0	0
Cenococcum sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	272	32	855	113	491	913	9	184	65	447	7	60	140	930	2159	214	0	0	17	512	2	27	71	6	2
Agaricales sp	288	8223	5082	11	151	4411	306	1467	1334	1371	14	354	3	279	601	10769	4541	12139	421	25665	5249	24	8928	420	11845	5	29	38	0	4881	0	2	3	113	0	247	0	2	6616	4736	0	12751	1025	1111	390	1434	0	24
Hydnotrya bailii	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	75	0	0	0	0	0	4	0	0	0	0	0	0	0	0	0	0	0	0	0
Serendipita herbamans	0	0	0	0	0	0	0	0	0	6	0	0	0	30	0	6	0	0	0	4	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Laccaria pumila	0	0	0	0	29	0	35	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Russula emetica	0	0	0	0	7063	0	0	0	0	0	0	0	967	0	0	0	0	0	13989	31574	92	716	644	0	0	16389	198	0	0	0	0	0	1401	260	15	0	0	0	0	0	44	0	1556	0	829	63	0	0
Polyozellus umbrinus	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	33	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Lactarius necator	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2732	0	0	126	0	148	0	48	5	8	0	1750	0	914	0	0	0	0	0	0	0	0	0	0
Imleria badia	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	126	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Hymenogaster rehsteineri	0	0	0	0	0	0	0	0	260	254	0	0	0	0	0	192	8	6	0	0	5	3	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	416	0	0	0	0	0	0	0	0
Tulasnella sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	4	0	0	0	0	0	11	0	0	0	0	30	0	2	0	0	0	0	0	0	0	0	0	0	0	0	21	0	0	4
Serendipita sp	0	0	0	0	0	189	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Meliniomyces sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	16	1728	0	66	3	27	9	55	13	26	3	0	229	65	17	196	0	11	6	12	15	0	0	0	19
Hyaloscypha vraolstadiae	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	13	0	7	972	312	342	0	59	0	0	0	0	166	0	3	7	8	139	54	0	0	2
Russula aeruginea	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	21	0	94	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Pezizaceae sp	0	0	0	0	91	0	0	0	4	0	0	0	0	0	0	0	30088	0	11570	0	39319	0	0	0	0	0	0	0	0	31	0	0	0	0	0	0	7	5	0	2	0	0	0	0	6	0	0	0
Cortinarius violaceus	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	37	0	0	0	0	0
Laccaria populina	2	8	87	1026	27400	4	5387	0	1934	427	3269	0	24402	14	0	6182	780	11	12853	8994	953	24450	15323	612	5358	14	2	0	0	2849	0	0	0	2	0	5	371	19	3741	18833	28	214	0	32	0	584	35	17
Entoloma sericatum	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	68	0	11	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Hyaloscypha fuckelii	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	192	77	0	0	0	5	0	22	0	0	7	0	2	1288	458	114	0	0	0	0	0	16	0	3	0
Hebeloma incarnatulum	0	0	2294	0	0	0	0	0	0	0	0	0	0	88	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	0	0	0	0	0	0	0	0	0	0	0	255	0	0	0
Thelephora atra	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1827	0	0	0	0	0	0	0	0	0	0	2	0	5	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Russula vinosa	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	1845	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Hyaloscypha variabilis	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	4	1593	1151	32	11	0	19	12	48	0	3	0	886	974	713	840	0	150	2	39	584	0	6	35	340
Tomentella sp	0	202	0	0	0	9354	2	300	12	5	142	0	0	0	0	193	0	964	471	13237	4	55	313	0	0	0	3	0	3	0	0	28	27	0	0	0	0	0	0	5	0	0	0	0	0	0	0	0
Entoloma chytrophilum	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	27	0	0	0	0	0	0	0	0	0
Hyaloscypha finlandica	1399	2622	15469	485	5136	320	1323	240	1560	1408	10325	1266	1764	846	2939	532	1773	267	733	7939	2120	4952	576	1356	8211	8879	407	1002	665	4944	830	1175	407	189	84	1044	1718	594	2650	1403	597	1445	1280	765	598	861	129	1768
Austroboletus mutabilis	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	12	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Sistotrema sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	15	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	0
Russula sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	4	0	0	0	25	91	62	57	120	34	26	40	72	74	9	13	125	70	97	71	0	42	12	11	41	75	20	29	31
Clavulina perplexa	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	27	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Ceratobasidium sp	0	0	0	5	0	2	0	0	0	0	0	0	0	23	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	0	0
Peziza echinospora	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	7	0	4	0	0	0	0	0	2	0	0	0	16	33	3	0	3	4	0	0	3	5	6	0
Paxillus ammoniavirescens	0	0	0	0	0	15	0	0	0	0	0	0	234	0	0	4	3	0	8171	0	6	0	0	0	0	2	3	0	0	4	0	4	577	0	0	134	0	0	138	0	4	0	0	824	226	7	0	0
Cortinarius ohlone	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	14	0	3	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Lactarius trivialis	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	13	0	4	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Lactifluus bicapillus	0	0	0	0	5	0	0	0	0	0	0	0	0	0	2	0	0	0	0	0	0	0	2	0	0	0	0	0	0	0	0	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Humaria hemisphaerica	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	10	0	0	0	0	0
Pezoloma sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	11	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Densospora sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	8	0	3	0	0	3	2	2	0	0	0	0	0	0	0	0	0	0	0	0	2	0	0	0
Helotiaceae sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	5	0	0	0	0	0	0	4	0	0	0	0	0	12	0	0	0	0	0	235	2	0	0	0
Inocybe acriolens	0	0	0	0	0	0	0	0	5	10	0	0	0	0	0	0	0	0	222	58	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	99	0	0	0	0	0	0	0	0
Laccaria moshuijun	0	0	0	0	2	0	0	0	0	0	0	0	11	0	0	0	0	0	0	3	0	4	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Thelephora sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	73	0	0	52	0
Inocybe napipes	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	13	0	0	0	0	0	0	0	0	0	0	0	0	0
Inocybe curvipes	0	22	3	218	3562	425	5	4	1189	215	1397	2164	0	0	21	486	20	9952	4246	9614	172	11228	6	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	319	0	0	0	0	0	115	0	0
Cadophora rotunda	0	0	0	0	0	0	0	0	0	12	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Russula pallescens	0	0	0	0	0	197	0	0	0	0	0	0	0	2186	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	0	0	0	0	0	0	0	0	0	0	0	0
Hebeloma vesterholtii	47	454	474	0	0	816	11	123	0	0	0	28	0	62	0	7	17	195	91	3506	15	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	0	0	0	0	0	0	158	0	0	0	0	0
Hymenogaster sp	0	0	0	0	2	0	0	0	0	0	0	0	0	0	0	350	0	0	0	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Hyaloscypha sp	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	14	0	0	0	0	0	0	0	0	0	0
Russula velenovskyi	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	151	127	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Inocybe vestalis	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	13	4	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Tylospora fibrillosa	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	6	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	5
Hyaloscypha gryndleri	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	318	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Ceratobasidiaceae sp	0	0	0	2	0	0	0	0	114	108	2	0	3	0	2	0	0	384	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Piloderma olivaceum	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	17	0	0
Hydnum melitosarx	0	0	0	0	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	37	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Pachyphlodes nemoralis	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	8	0	0	0	12	0	0	0	0	0	0	0	0	0	0	38	2728	0	0	0
Tarzetta alnicola	0	0	0	0	0	0	0	0	0	0	0	0	0	1356	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Cortinarius intempestivus	0	0	0	149	140	1531	0	0	780	803	0	0	4154	0	0	0	0	0	265	18939	9	1887	494	0	2	0	0	0	0	0	0	0	0	0	0	2	0	2	0	32	0	0	0	0	0	55	0	0
Boletus edulis	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	4	21	0	0	0	0	0	0	0	0	0	0	12	0	0	0	0	0
Hymenoscyphus menthae	2	0	31	0	1287	0	0	16	39	83	0	2	0	0	0	4	0	928	0	3	43	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2400	0	0	0	0	0	0	0	0
Chloridium chloridioides	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	6	0	0	0	0	0	0	0	0	6	0	0	0	0	0	0	0	2	0	0	0	0	0	0	0	0	0
Lactarius rufus	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	22	3	0	0	0	0	0	0	0	0	0	9975	0	6	0	0	0	149	0	56	0	0	0	0
Amanita fulva	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2188	0	0	0	0	0	0	0	0	0	0	919	616	0	0	28	0	145	0	0	0	0	0
Lactarius camphoratus	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	21	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Peziza ostracoderma	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2716	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Russula violaceoincarnata	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	18	23	0	26	0	0	0	0	566	0	0	0	0	0	0	0	0	0	0	0	0	0
Tuber rufum	0	0	0	0	0	0	4114	0	0	0	0	0	0	0	0	0	0	0	0	0	0	2	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Amanita rubescens	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	607	0	0	0	0	0	0	0	0	0	0	0	0	0	76	0	0	0
Piloderma sphaerosporum	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	97	292	28	0	0	0	0	0	3	0	0	135	538	1545	189	0	591	0	0	31	0	0	199	1895
Hyaloscypha gabretae	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	13	125	0	0	0	0	0	2	0	0	0	0	0	8	13	0	0	0	0	8	0	0	0	0
Inocybe pseudodestricta	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	248	0	0	0	0	0
Entoloma nidorosum	664	2	127	0	0	0	0	0	0	0	0	730	0	0	0	0	0	0	0	0	0	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Pyronemataceae sp	0	0	8	0	0	2	14	2	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Boletus satanas	0	0	0	2	0	2	0	3	0	0	0	0	3	3	0	0	0	0	2	2	0	4	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
