'Birke' was Germany’s evacuation of its military forces from Finland after the collapse of Finnish resistance to the USSR at the end of the 'Jatkosota' continuation war (3 September 1944/April 1945).

Finnish attempts to find an acceptable exit from the 'Jatkosota' in the spring of 1944 greatly alarmed the Germans, who had sizeable quantities of stores in northern Finland and feared that a Finnish departure from the war would leave these vulnerable to Soviet seizure, and also open the way for a Soviet advance into northern Norway. In April 1944, therefore, the Germans started a high-intensity effort to reconnoitre and construct defensive positions against possible advances from the south.

Since existing German stocks of nickel were deemed sufficient and new deposits had been located in Austria, the importance to Germany of holding Petsamo region and/or Finnish Lapland had by this time decreased considerably. At the same time the logistical and military difficulties of defending northern Finland had been fully appreciated. These factors therefore made it possible for the Germans, on 4 October 1944, to gain Hitler’s approval for moving from 'Birke' to 'Nordlicht' (iii), abandoning the northern part of Finland and fortifying the lines of withdrawal to Lyngen in the northern region of Norway.

The 'Birke' withdrawal which these measures would protect was effected on a step-by-step basis from 3 September in the form of the retirement of the front line first to the Sohjana position, and then from 15 September to the Kuusamo position.

It was from a time as early as November 1941 that Finland had lost its enthusiasm for any continued prosecution of the war after its forces had recaptured those areas of the country lost to the USSR in the 'Talvisota' winter war of 1939/40, and further grist was added to the mill of growing Finnish disaffection with the war effort during the following month by the failure of the German 'Taifun' (i) offensive against Moscow and the US entry into the war on the Allied side. Thus the Finnish government, headed by Suomen marsalkka Carl Gustaf Emil Mannerheim, rapidly reached the conclusion that the USSR would probably not be defeated in the immediate future. Even so, the Finns disregarded a Soviet peace feeler received through the Swedish foreign ministry at the end of 1941, and during 1942 came under renewed pressure from each side: Germany wanted Finland to undertake another operation to cut the railway extending to the south from Murmansk into Russia, while exactly the opposite was urged by the USA, with which Finland was not at war.

Finland was all too aware of the steady decline in Germany’s strategic position during the second half of 1942 and throughout 1943 as the British and Americans prevailed in North Africa and then invaded Italy, which changed sides, as the Soviets scored stunning successes at Stalingrad and Kursk, and as Allied bombing started to make serious inroads into Germany’s war-making capabilities. The obvious conclusion was that Germany could no longer win the war, and the Finnish government accordingly decided to look for a way out of the war as quickly as it could.

While he placed a heavy reliance on subordinates such as Jalkaväenkenraali Axel Erik Heinrichs, Kenraaliluutnantti Karl Lennart Oesch and Kenraaliluutnantti Hjalmar Fridolf Siilasvuo, the elderly Mannerheim was still commander-in-chief of the Finnish armed forces and the dominant figure in Finnish affairs. Mannerheim was essentially pro-German, and always conscious of the German aid Finland had received in 1917/18 in its struggle to secure independence from Russia, was on good terms with Adolf Hitler, but was concerned overwhelmingly with his perception of what was right for Finland. Thus in the middle of 1941 Mannerheim felt that Finland’s future lay in an alliance with Germany, by December of the same year he was beginning to have doubts, and by 1942 he had decided that Finland’s best option was a policy of obstruction and inactivity.

By the autumn of 1943 Finland still had more than 350,000 men under arms facing some 180,000 Soviet troops, while in the north Generaloberst Eduard Dietl’s 20^th Gebirgsarmee had more than 180,000 combat troops in General Friedrich Hochbaum’s XVIII Gebirgskorps (Generalmajor Mathias Kräutler’s Divisionsgruppe 'K' or Division zbV 140, Generalleutnant August Krakau’s 7^th Gebirgsdivision, SS-Gruppenführer und Generalleutnant der Waffen-SS Karl Brenner’s 6^th SS Gebirgsdivision 'Nord', the MG-Skibrigade 'Finnland' and the 211^th Panzerabteilung less one company), General Emil Vogel’s XXXVI Gebirgskorps(Generalleutnant George Radziej’s 169^th Division, Generalleutnant Karl Rübel’s 163^rd Division and the 1/211^th Panzerabteilung), and General Ferdinand Jodl’s XIX Gebirgskorps (Generalleutnant Max Pemsel’s 6^th Gebirgsdivision strengthened with the 388^th Grenadierbrigade, Generalleutnant Hans Degen’s 2^nd Gebirgsdivision, Generalleutnant Kurt Ebeling’s 210^th Division, and Generalmajor Adrian Freiherr van der Hoop’s Divisionsgruppe 'van der Hoop' comprising the 193^rd and 503^rd Grenadierbrigaden), and outnumbered the Soviet forces facing it by 2/1.

The Finns nonetheless held the centre and south of the front against the Soviets, and the Germans appreciated that they could achieve little on this front without Finnish agreement and support. Dietl and the German liaison officer at Mannerheim’s headquarters agreed that Finland’s unwillingness to attempt a severing of the Murmansk railway and the destruction of the Soviet armies facing them was the result of Finnish fear of alienating the USA, but the reality was a mix of this and the Finnish appreciation that the Murmansk railway was not totally vital to the USSR, and that any attempt to destroy the Soviet 7^th Army and 23^rd Army would also have resulted in heavy Finnish losses. Even so, the Finns also knew that the conditions of any Soviet-dictated peace would almost certainly be very difficult, so in July 1943 they again rejected a Soviet proposal to end the 'Jatkosota', even though the continued presence in Finland of the 20^th Gebirgsarmee was becoming problematical.

Seeing the way in which Finnish matters were likely to turn, on 28 September 1943 Hitler ordered the 20^th Gebirgsarmee to plan and prepare to hold northern Finland and the strategically important nickel mines at Petsamo in the event that the Finns reached terms with the Soviets. Dietl objected in vain to Generaloberst Alfred Jodl, head of the Oberkommando der Wehrmacht’s operations staff, that this was not realistic, for he was sure that he could not hold northern Finland over any extended period, especially as Swedish neutrality was no longer wholly assured. The orders stood, however, so in the winter of 1943/44 the 20^th Gebirgsarmee improved the road from northern Norway to northern Finland, largely through extensive use of prisoner-of-war labour (many such captives had been taken in southern Europe and were wearing lightweight uniforms, so losses were high), and also built up its stores in the region.

In January 1944 the Soviet 'Leningrad-Novgorod Strategic Offensive Operation' to the south of Leningrad forced Generalfeldmarschall Georg von Küchler’s (from 9 January Generalfeldmarschall Walter Model’s) Heeresgruppe 'Nord' back toward the Baltic states, and this further worried the Finns, who rightly feared all but the most tenuous isolation from their primary ally, who was also largely responsible for Soviet pressure on the Finns.

In middle of February the Finnish government finally sent emissaries to Moscow, but the peace conditions which the Soviets demanded were so harsh that the Finns again rejected them. Hitler retaliated by restricting arms and grain shipments to Finland.

Iosif Stalin, the Soviet dictator, had already come under pressure, at the 'Sextant' conference at Tehran in December 1943, from President Franklin D. Roosevelt and Prime Minister Winston Churchill, to assure the continued independence of Finland, and reluctantly agreed. However, Stalin had also decided to remove the Finnish thorn from the Soviet flank in the north.

Thus General Leytenant Dmitri N. Gusev’s 21^st Army of six infantry divisions and a breakthrough artillery corps was transported by sea across the Gulf of Finland from Oranienbaum to the area north of Leningrad, and a further nine infantry divisions and a breakthrough artillery division were added to General Leytenant Aleksei N. Krutikov’s 7^th Army on the left wing of the Karelia Front. General Leonid A. Govorov’s Leningrad Front was concentrated on the narrow Karelian isthmus, between the Gulf of Finland and Lake Ladoga, to the north-west of Leningrad, and comprised the newly arrived 21^st Army of 10 divisions on the left and General Leytenant Aleksandr I. Cherepanov’s 23^rd Army of eight divisions on the right. The left wing of Marshal Sovetskogo Soyuza Kirill A. Meretskov’s Karelia Front farther to the north comprised Krutikov’s 7^th Army of 14 infantry divisions on the Svir river between Lake Ladoga and Lake Onega, and General Leytenant Filipp D. Gorelenko’s 32^nd Army of only three divisions to the north of Lake Onega.

For this offensive the Leningrad Front and the Karelia Front were to use about 45 divisions and a number of tank and marine brigades, totalling almost 500,000 men, 800 tanks and self-propelled guns, and about 1,500 aircraft. Some 10,000 guns and mortars were said to be available for the attack, together with some large-calibre guns of the warships of Vitse Admiral Vladimir F. Tributs’s Baltic Fleet.

The Soviet plan was to make a primary thrust through the Karelian Isthmus on the 21^st Army’s sector toward Viipuri, while the 23^rd Army would attempt to pin the bulk of the Finnish forces against Lake Ladoga and the small lakes to the Finnish rear. Govorov failed to make any provision for securing the neck of the isthmus to the east of Viipuri in order to cut the Finnish forces' only line of withdrawal.

The Finnish troops defending the 30-mile (48-km) width of the Karelian isthmus were grouped under Siilasvuo’s III Armeijakunta (corps) and Kenraaliluutnantti Taavetti Laatikainen’s IV Armeijakunta, and comprised three infantry divisions and a brigade deployed forward in the line, with two more divisions and a cavalry brigade in the rear working on the defences. The Finnish defences consisted of two main defensive zones, the forward zone comprising a forward line with a second 'VT-linj' as a fallback position about 10 miles (16 km) to the rear, the rear zone consisting of a third 'VET-linj' across the narrow neck of the isthmus, 30 miles (48 km) back and immediately to the east of Viipuri. A fourth incomplete defence line, on the old 1940 frontier and thus known as the 'Moscow linj', was located still farther to the rear. The forward three lines were well sited and organised, although they consisted mainly of earthworks strengthened with concrete and steel emplacements.

The Soviet high command had no illusions as to the severity of the fighting to which it was about to commit its troops. The Western Allies had just launched their 'Overlord' landing in Normandy and the Soviets were in the last stages of planning their great 'Bagration' offensive to clear Belorussia and sweep forward into Poland and the Baltic states, but saw that the time was ripe to drive Finland out of the war in an offensive whose secondary objectives were the diversion of German attention from the Belorussian front, the improvement of Leningrad’s security, and the reopening of the Kirov route and the White Sea Baltic Canal.

On 9 June the Soviet air forces made heavy bombing attacks, and on the following day a very heavy artillery barrage presaged the launch of the offensive as the 21^st Army crossed the Sestra river and penetrated 10 miles (16 km) into the Finnish defences. One day later, the 23^rd Army went over to the offensive on the right, and on 13 June the Soviet forces reached the second 'VT-linj'. Here the Finns wrongly inferred that the main weight of the Soviet offensive was in its centre, whereas it was in fact on its left along the coastal road. Here, with the support of the III Breakthrough Artillery Corps and armour which the Finns found its hard to counter, the Soviet forces drove an 8-mile (13-km) gap through the Finnish defences on 14 June. On 18 June Soviet troops were approaching Viipuri. A few days earlier the Finns had called on the Germans to lift their embargo on arms deliveries, and to provide six divisions for the quiet sector in Karelia, so allowing the Finnish formations currently deployed there to be moved toward the Viipuri sector.

The Germans had few troops to spare for Finland, but Hitler did make available Generalmajor Hero Breusing’s 122^nd Division and one brigade of about 30 self-propelled assault guns. Air support by Luftwaffe units was also increased, and a combined air and sea lift was organised to deliver 9,000 Panzerfaust and 5,000 Panzerschreck short-range anti-tank weapons.

The renewed German involvement also included Joachim Ribbentrop, the foreign minister, who demanded a signed commitment by President Risto Ryti that Finland would not make a separate peace.

On the front, the Finns had already committed their only armoured division and were starting to move formations from Karelia to the Viipuri sector of the isthmus front. The Finns also felt that better co-ordination of the defence could be achieved by a single commander, and Oesch was appointed to supervise the operations of the III Armeijakunta and IV Armeijakunta. The fighting was continuous, bitter and, according to the Finns, the more severe of the whole war. Although Eversti Jussi Sihvo’s (from 17 June Eversti Kai Savonjousi’s) 10^th Divisioona (division), which had borne the brunt of the initial Soviet offensive, had been decimated to a state of ineffectiveness, the other divisions managed to withdraw in fighting order north of Viipuri, this being attributable, in part at least, to the Soviets' failure to close the narrow land exit of the isthmus. Viipuri fell on 20 June, but shortly after this the Soviets halted their offensive on the isthmus front.

However, on the following day Meretskov launched the next offensive in eastern Karelia against the weakened Finnish positions on the Svir river to the east of Lake Ladoga and to the north of Lake Onega, from which the Finns had already begun to pull back. Kenraalimajuri Antero Svensson’s V Armeijakunta had been transferred to the isthmus to help stem Govorov’s offensive, so the rearguard action against the 7^th Army on the Svir river was carried out by Kenraalimajuri Aarne Blick’s (from 6 July Kenraalimajuri Armas-Eino Martola’s) VI Armeijakunta and Kenraaliluutnantti Paavo Talvela’s 'Aunuksen' Ryhmä ('Olonets' Group), while Kenraalimajuri Einar Mäkinen’s II Armeijakunta defended the area of Velikaya Guba to the north of Lake Onega against the 32^nd Army.

The Finns mined and demolished the area as they withdrew, but were unable to break contact with the advancing Soviet forces and the fighting was at times very severe.

Over a period of some six weeks, the Finns yielded most of the territory they had gained in 1941, but nearing the end of July the Soviet pressure eased as formations were sent south into the Baltic states, where the German line was being ripped apart by the Belorussian offensive. German assistance to Finland inevitably petered out as their own requirements took priority, and on 29 July Hitler demanded the return of the 122^nd Division.

In Finland, the German defeat in Belorussia and the Baltic states combined with the German inability to beat back 'Overlord' and its exploitation to convince the Finns that Germany’s strength was fast ebbing. There was also anger over Germany’s failure to honour its part of the Ryti-Ribbentrop agreement. On 4 August Ryti was succeeded as president by Mannerheim, allowing the Finns to repudiate Ryti’s agreement with the Germans. The Germans sent first Schörner, commander of Heeresgruppe 'Nord' and an erstwhile commander of the 6^th Gebirgsdivision and then the XIX Gebirgskorps in Finland, and then Generalfeldmarschall Wilhelm Keitel, head of the Oberkommando der Wehrmacht, who were each told by Mannerheim that Finland had suffered more than 60,000 casualties during the latest bout of fighting, and that the Ryti-Ribbentrop agreement was no longer valid.

Immediately after the arrival of news of fighting between German and Romanian forces after Romania had sued for peace, on 25 August the Finns asked the Soviets for terms, and the Soviets agreed to the arrival of a Finnish delegation in Moscow on condition that Finland broke of relations with Germany, and ensured the removal of all foreign troops from Finnish soil by 15 September. Dietl, the German commander in Finland, had lost his life in an air accident on 23 June, and was succeeded by Generaloberst Dr Lothar Rendulic. The new commander urged Mannerheim not to turn on the Germans, but Mannerheim felt that he must accede to the USSR’s demand, especially as the 20^th Gebirgsarmee could not readily be reinforced and was outnumbered by some 2/1 by the Finns.

The Germans began to withdraw their stores and munitions from the first week in September, but could clearly not leave Finland by the date demanded in the middle of the month without abandoning most of their heavy equipment. The relations in Finland between the Germans and the Finns remained basically good until the German naval staff persuaded Hitler to agree to the 'Tanne Ost' attempt to seize the Finnish naval base on Suursaari island in the Gulf of Finland. The German attack took place in the morning of 15 September and, contrary to German expectations, the Finnish garrison fought back and, with Soviet air support, drove off the assault of the Germans, whose men suffered heavy losses.

The German attack on Suursaari played into Soviet hands and allowed the Finns to escape from a difficult situation. Mannerheim responded by ordering all Finnish vessels to cease operations and return to base, and by asking for the 20^th Gebirgsarmee's instant removal. There was still no hint of direct Finnish action against the Germans in Finland, however, and Rendulic noted that while the Finns were under intense Soviet pressure to become more active, he regarded the Finnish follow-on to the German withdrawal toward northern Norway and the head of the Gulf of Bothnia as an effort to satisfy Soviet demands. Thus the German withdrawal was without incident until the German troops were pressed by the Finns commanded by Siilasvuo.

The first moderately serious fighting took place at Kemi-Tornio at the north end of the Gulf of Bothnia, and during October and November 1944 Siilasvuo’s forces drove the last elements of the 20^th Gebirgsarmee out of most of northern Finland. There was hard fighting at Tankavaara and Kaunispää, where the Germans made a stand to cover their westward retirement toward Norway. In the later stages of their withdrawal the German forces devastated large areas of northern Finland in a scorched earth policy. More than one-third of the buildings in the area were destroyed, and the provincial capital of Rovaniemi was burned to the ground after an ammunition train had blown up. Throughout Lapland only two bridges survived, and the area’s roads were extensively mined. In addition to the area’s losses in property, about 100,000 of its inhabitants became refugees, a situation that added to the problems of post-war reconstruction.

The last German troops were expelled only in April 1945, but by that time only 600 Finnish troops, most of them new recruits, were facing them as a result of the Soviet demand for Finnish demobilisation. The military casualties of this campaign were light: Finland lost 773 men killed, 262 missing and about 3,000 wounded, while the Germans lost 950 men killed, about 2,000 wounded and 1,300 taken prisoner. The Soviets had revealed little initial inclination to press matters on the ground, and it was 15 October before the first Soviet troops moved forward to occupy the Petsamo area. So ended the Finnish War, a war which cost Finland about 200,000 casualties including 55,000 dead.